MIPS: LLVMLinux: Silence variable self-assignment warnings.

Remove variable self-assignments.
This silences a bunch of -Wself-assign warnings reported by clang.
The changed code can be compiled without warnings by both gcc and clang.

Signed-off-by: Toma Tabacu <toma.tabacu@imgtec.com>
Signed-off-by: Daniel Sanders <daniel.sanders@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9314/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>