extcon: max8997: Fix checkpatch error

Fixes the following checkpatch error:
ERROR: space required after that ',' (ctx:VxV)
460: FILE: extcon/extcon-max8997.c:460:
		ret = request_threaded_irq(virq, NULL,max8997_muic_irq_handler,
		                                     ^

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>