[lld] [LLD][ELF][RISCV][Zicfilp][Zicfiss] Support `-z zicfilp=` and `-z zicfiss=` to force enable/disable features (PR #143114)

[Fangrui Song via llvm-commits]

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@@ -29,18 +36,33 @@
 # RUN: ld.lld f2-s.o f3.o --shared -o out.no.so --fatal-warnings
 # RUN: llvm-readelf -n out.no.so | count 0
 
+## ZICFILP-func-sig should be disabled with zicfilp=never, even if
+## ZICFILP-func-sig is present in all inputs
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MaskRay wrote:

End complete sentences in comments with a full stop.

https://github.com/llvm/llvm-project/pull/143114