arm64: use __func__ to get function name in pr_err

Prefer using '"%s...", __func__' to get current function's name in
a debug message.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210726122907.51529-1-wangborong@cdjrlc.com


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