regulator: rpi-panel-attiny-regulator: Remove redundant of_match_ptr()

regulator: rpi-panel-attiny-regulator: Remove redundant of_match_ptr()

The driver depends on CONFIG_OF, so it is not necessary to use
of_match_ptr() here, and __maybe_unused can also be removed.

Even for drivers that do not depend on CONFIG_OF, it's almost always
better to leave out the of_match_ptr(), since the only thing it can
possibly do is to save a few bytes of .text if a driver can be used both
with and without it.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20230807134127.2380390-1-ruanjinjie@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>