extcon: max8997: Delete unneeded initialization in max8997_muic_set_path()

The variable "ret" will be set to an appropriate value a bit later.
Thus this patch omits the explicit initialization at the beginning.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>