Restore bootstrap on x86_64-pc-linux-gnu

This patch resolves the bootstrap failure on x86_64-pc-linux-gnu.

2022-02-22  Roger Sayle  <roger@nextmovesoftware.com>

gcc/ChangeLog
	* config/i386/i386-expand.cc (ix86_expand_cmpxchg_loop): Restore
	bootstrap.