regmap: Don't check for changes in regcache_set_val()

The only user of regcache_set_val() ignores the return value so we may as
well not bother checking if the value we are trying to set is the same as
the value already stored.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230609-regcache-set-val-no-ret-v1-1-9a6932760cf8@kernel.org


Signed-off-by: Mark Brown <broonie@kernel.org>