[scudo/standalone] Use .arch_extension memtag, not mte

GNU binutils accepts only `.arch_extension memtag` while Clang
accepts either that or `.arch_extension mte` to mean the same thing.

Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D95996

GitOrigin-RevId: 4c9adbb287e7e6cfea866b3c3254b50f21e5ce1f
1 file changed