mfd: max77693: Use proper regmap for handling MUIC interrupts

Interrupts coming from Maxim77693 MUIC block (MicroUSB Interface
Controller) were not handled at all because wrong regmap was used for
MUIC's regmap_irq_chip.

The MUIC component of Maxim 77693 uses different I2C address thus second
regmap is created and used by max77693 extcon driver. The registers for
MUIC interrupts are also in that block and should be handled by that
second regmap.

However the regmap irq chip for MUIC was configured with default regmap
which could not read MUIC registers.

Fixes: 342d669c ("mfd: max77693: Handle IRQs using regmap")

Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>