MIPS: microMIPS: Add instruction utility macros.

MIPS: microMIPS: Add instruction utility macros.

Add two new macros for microMIPS. One checks if an exception was
taken in either microMIPS or classic MIPS mode. The other checks
if a microMIPS instruction is 16-bit or 32-bit in length.

[[email protected]: Removed unnecessary parenthesis as noted by
Sergei Shtylyov <[email protected]>]

Signed-off-by: Steven J. Hill <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Sergei Shtylyov <[email protected]>
Patchwork: https://patchwork.linux-mips.org/patch/4924/
Signed-off-by: Ralf Baechle <[email protected]>
(cherry picked from commit 49df26472338b935fd5781bf94a77a88b148a716)