MIPS: memset.S: Reinstate delay slot indentation

Assembly language within the MIPS kernel conventionally indents
instructions which are in a branch delay slot to make them easier to
see. Commit 8483b14a

 ("MIPS: lib: memset: Whitespace fixes") rather
inexplicably removed all of these indentations from memset.S. Reinstate
the convention for all instructions in a branch delay slot. This
effectively reverts the above commit, plus other locations introduced
with MIPSR6 support.

Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/19111/
Signed-off-by: James Hogan <jhogan@kernel.org>