MIPS: inst.h: Add new MIPS R6 FPU opcodes

Add opcodes for the new MIPS R6 FPU instructions.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10952/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>