We always either target MIPS32/MIPS64 or microMIPS, and always include
one & only one of uasm-mips.c or uasm-micromips.c. Therefore the
abstraction of the ISA in asm/uasm.h declaring functions for either ISA
is redundant & needless. Remove it to simplify the code.

This is largely the result of the following:

  :%s/ISAOPC(\(.\{-}\))/uasm_i##\1/
  :%s/ISAFUNC(\(.\{-}\))/\1/
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paul Burton <paul.burton@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/15844/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>