Use regmap_assign_bits() where it improves readability. With this
there is no need to calculate masks and values in separate lines.
Splitting the single update_bits() in rtmdio_931x_setup_polling()
into two separate assign_bits() is uncritical.
Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/23099
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>