Add support for Intel SGX instructions

Add Intel SGX instructions support to assembler and disassembler.

gas/

	* config/tc-i386.c (cpu_arch): Add .se1.
	* doc/c-i386.texi: Document .se1/se1.

gas/testsuite/

	* gas/i386/i386.exp: Run SE1 tests.
	* gas/i386/se1.d: New file.
	* gas/i386/se1.s: Ditto.
	* gas/i386/x86-64-se1.d: Ditto.
	* gas/i386/x86-64-se1.s: Ditto.

opcodes/

	* i386-dis.c (rm_table): Add encls, enclu.
	* i386-gen.c (cpu_flag_init): Add CPU_SE1_FLAGS,
	(cpu_flags): Add CpuSE1.
	* i386-opc.h (enum): Add CpuSE1.
	(i386_cpu_flags): Add cpuse1.
	* i386-opc.tbl: Add encls, enclu.
	* i386-init.h: Regenerated.
	* i386-tbl.h: Likewise.