[Bug c/70210] -march=native and -mcpu=native do not detect ARM cortex-a53 in 32 bit mode on Linux

[andrewm.roberts at sky dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70210

--- Comment #1 from Andrew Roberts <andrewm.roberts at sky dot com> ---
Note this was causing bug 70132 (ARM -mcpu=native can cause a double free
abort). 
A patch as been subitted to fix the double free, but doesn't address 
the failure to detect the CPU