Add in a JALRC alias and fix the NAL instruction.

opcodes/

	* mips-opc.c (mips_builtin_opcodes): Add JALRC alias for JIALC.
	Remove the operand from NAL.

gas/testsuite/

	* gas/mips/r6.s: Test JALRC and NAL
	* gas/mips/r6-n32.d: Add expected output for JALRC and NAL.
	* gas/mips/r6-n64.d: Likewise.
	* gas/mips/r6.d: Likewise.