[Bug target/108853] Add new -mcpu=e500 alias for -mcpu=8540

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108853

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
e500 support was mostly removed out of GCC too.