[clang] [clang][ARM] disable frame pointers by default for bare metal ARM targets (PR #117140)

[Ties Stuij via cfe-commits]

stuij wrote:

This change was discussed in the LLVM Embedded Toolchains working group sync up two weeks ago, and at the time people were in agreement that it made sense:

https://discourse.llvm.org/t/llvm-embedded-toolchains-working-group-sync-up/63270/73#p-334070-peter-frame-pointers-on-or-off-by-default-7

https://github.com/llvm/llvm-project/pull/117140