microblaze: cache: introduce flush_cache_all()

microblaze: cache: introduce flush_cache_all()

All flush_cache() calls in microblaze code are supposed to flush the
entire instruction and data caches, so introduce flush_cache_all()
helper to handle this.

Also, provide implementations for flush_dcache_all() and
invalidate_icache_all() so that icache and dcache u-boot commands can
work.

Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
Link: https://lore.kernel.org/r/20220531181435.3473549-9-ovpanait@gmail.com
Signed-off-by: Michal Simek <michal.simek@amd.com>