MIPS: Adjust set_pte() SMP fix to handle R10000_LLSC_WAR

MIPS: Adjust set_pte() SMP fix to handle R10000_LLSC_WAR

Update the recent changes to set_pte() that were added in 7861143782d3
to handle R10000_LLSC_WAR, and format the assembly to match other areas
of the MIPS tree using the same WAR.

This also incorporates a patch recently sent in my Markos Chandras,
"Remove local LL/SC preprocessor variants", so that patch doesn't need
to be applied if this one is accepted.

Signed-off-by: Joshua Kinard <kumba@gentoo.org>
Fixes: 7861143782d3 ("MIPS: Make set_pte() SMP safe.)
Cc: David Daney <david.daney@cavium.com>
Cc: Linux/MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/11103/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>