MIPS: cps-vec: Use macros for 64bits access

Some access are 32 bits only while they seems better to be done in
64bis for 64 bit kernel.

This was extract from an initial patch from Jiaxun

Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>