[mips] Fix two patterns that select i32's (for MIPS32r6) / i64's (for MIPS64r6)
from setne comparison with an i32.

The patterns that are fixed:
  * (select (i32 (setne i32, immZExt16)), i32, i32) (for MIPS32r6)
  * (select (i32 (setne i32, immZExt16)), i64, i64) (for MIPS64r6)