[llvm] Hexagon: Add runtime libcall entries for volatile memcpy call (PR #156561)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `cross-project-tests-sie-ubuntu-dwarf5` running on `doug-worker-1b` while building `llvm` at step 6 "test-build-unified-tree-check-cross-project".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/163/builds/26035

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-cross-project) failure: test (failure)
******************** TEST 'cross-project-tests :: debuginfo-tests/dexter-tests/memvars/unused-merged-value.c' FAILED ********************
Exit Code: 2

Command Output (stdout):
--
unused-merged-value.c: nan/nan (nan) [Command '['/usr/bin/python3.10', '/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/cross-project-tests/debuginfo-tests/dexter/dex/../dexter.py', 'run-debugger-internal-', '/tmp/lit-tmp-uvah_6dr/dexter/tmpb9bjyy6p/tmpjpcjsm0f', '--working-directory=/tmp/lit-tmp-uvah_6dr/dexter/tmpb9bjyy6p', '--unittest=off', '--indent-timer-level=3']' returned non-zero exit status 1.]


--
Command Output (stderr):
--
/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/bin/clang -std=gnu11 -O3 -glldb /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/cross-project-tests/debuginfo-tests/dexter-tests/memvars/unused-merged-value.c -o /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/projects/cross-project-tests/debuginfo-tests/dexter-tests/memvars/Output/unused-merged-value.c.tmp # RUN: at line 8
+ /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/bin/clang -std=gnu11 -O3 -glldb /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/cross-project-tests/debuginfo-tests/dexter-tests/memvars/unused-merged-value.c -o /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/projects/cross-project-tests/debuginfo-tests/dexter-tests/memvars/Output/unused-merged-value.c.tmp
"/usr/bin/python3.10" "/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/cross-project-tests/debuginfo-tests/dexter/dexter.py" test --fail-lt 0.1 -w --lldb-executable "/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/bin/lldb-dap" --debugger lldb-dap --binary /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/projects/cross-project-tests/debuginfo-tests/dexter-tests/memvars/Output/unused-merged-value.c.tmp -- /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/cross-project-tests/debuginfo-tests/dexter-tests/memvars/unused-merged-value.c # RUN: at line 9
+ /usr/bin/python3.10 /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/cross-project-tests/debuginfo-tests/dexter/dexter.py test --fail-lt 0.1 -w --lldb-executable /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/bin/lldb-dap --debugger lldb-dap --binary /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/projects/cross-project-tests/debuginfo-tests/dexter-tests/memvars/Output/unused-merged-value.c.tmp -- /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/cross-project-tests/debuginfo-tests/dexter-tests/memvars/unused-merged-value.c


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```

</details>

https://github.com/llvm/llvm-project/pull/156561