x86: Remove CpuABM and add CpuPOPCNT

x86: Remove CpuABM and add CpuPOPCNT

AMD ABM has 2 instructions: popcnt and lzcnt.  ABM CPUID feature bit has
been reused for lzcnt and a POPCNT CPUID feature bit is added for popcnt
which used to be the part of SSE4.2.  This patch removes CpuABM and adds
CpuPOPCNT.  It changes ABM to enable both lzcnt and popcnt, changes SSE4.2
to also enable popcnt.

gas/

	* config/tc-i386.c (cpu_arch): Add .popcnt.
	* doc/c-i386.texi: Remove abm and .abm.  Add popcnt and .popcnt.
	Add a tab before @samp{.sse4a}.

opcodes/

	* i386-gen.c (cpu_flag_init): Replace CpuABM with
	CpuLZCNT|CpuPOPCNT.  Add CpuPOPCNT to CPU_SSE4_2_FLAGS.  Add
	CPU_POPCNT_FLAGS.
	(cpu_flags): Remove CpuABM.  Add CpuPOPCNT.
	* i386-opc.h (CpuABM): Removed.
	(CpuPOPCNT): New.
	(i386_cpu_flags): Remove cpuabm.  Add cpupopcnt.
	* i386-opc.tbl: Replace CpuABM|CpuSSE4_2 with CpuPOPCNT on
	popcnt.  Remove CpuABM from lzcnt.
	* i386-init.h: Regenerated.
	* i386-tbl.h: Likewise.