mfd: Rely on regmap cache in wm8350 interrupt controller

We can just use regmap_update_bits() to achieve the same effect - it will
do the read/modify/update cycle for us.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --cc drivers/mfd/wm8350-irq.c
Simple merge