soc: mediatek: pm-domains: Simplify some error message

dev_err_probe() already prints the error code in a human readable way, so
there is no need to duplicate it as a numerical value at the end of the
message.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/e6ba80d8e27fdb2b1527c7eae6687e481960c81d.1659735996.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>