clk: mediatek: reset: Extract common drivers to update function

clk: mediatek: reset: Extract common drivers to update function

To make drivers more clear and readable, we extract common code
within assert and deassert to mtk_reset_update_set_clr() and
mtk_reset_update().

Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220523093346.28493-5-rex-bc.chen@mediatek.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>