MIPS: microMIPS: Fix POOL16C minor opcode enum

MIPS: microMIPS: Fix POOL16C minor opcode enum

As pointed out by Maciej, POOL16C minor opcodes were mostly shifted
by one bit. Correct those opcodes, and also add jraddiusp to the enum.

Signed-off-by: Tony Wu <tung7970@gmail.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Acked-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: david.daney@cavium.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5527/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>