[Bug target/121971] [15/16 Regression] Only warn about musttail on exotic targets?

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121971

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Also arm and ppc are not that "exotic". They are/were mainstream processors and
have a backend in llvm too.