Initial Fast Short REP MOVSB (FSRM) support

The newer Intel processors support Fast Short REP MOVSB which has a
feature bit in CPUID.  This patch adds the Fast Short REP MOVSB (FSRM)
bit to x86 cpu-features.

	* sysdeps/x86/cpu-features.h (bit_cpu_FSRM): New.
	(index_cpu_FSRM): Likewise.
	(reg_FSRM): Likewise.