Revert "MIPS: UAPI: Fix unrecognized opcode WSBH/DSBH/DSHD when using MIPS16."

Revert "MIPS: UAPI: Fix unrecognized opcode WSBH/DSBH/DSHD when using MIPS16."

This reverts commit 9f69841ab9a6d4d818542efce492fd56dafe843a.

For at least GCC 4.8.3, adding nomips16 function attribute still cannot
prevent it from being inlined in mips16 context.  So revert it first in
preparation for a better workaround.

 [1] Inlining nomips16 function into mips16 function can result in
     undefined builtins, https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55777

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11240/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>