arm64: unnecessary end 'return;' in void functions

The end 'return;' in a void function is useless and verbose. It can
be removed safely.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Link: https://lore.kernel.org/r/20210726123940.63232-1-wangborong@cdjrlc.com


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>