arm64: lib: Use MOPS for copy_page() and clear_page()

arm64: lib: Use MOPS for copy_page() and clear_page()

Similarly to what was done to the memcpy() routines, make copy_page()
and clear_page() also use the Armv8.8 FEAT_MOPS instructions.

Note: For copy_page() this uses the CPY* instructions instead of CPYF*
as CPYF* doesn't allow src and dst to be equal. It's not clear if
copy_page() needs to allow equal src and dst but it has worked so far
with the current implementation and there is no documentation forbidding
it.

Note, the unoptimized version of copy_page() in assembler.h is left as
it is.

Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Link: https://lore.kernel.org/r/20240930161051.3777828-6-kristina.martsenko@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>