[Bug target/124094] aarch64: poor diagnostics for bad inputs to -muser-provided-CPU=

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124094

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note this option is not supposed to be used except by gcc developers so I am
not sure it matters.