media: m5mols: Convert to use GPIO descriptors

The Fujitsu M5MOLS sensor driver is using a reset GPIO number
passed from platform data.

No machine/board descriptor file in the kernel is using this so
let's replace it with a GPIO descriptor.

Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Heungjun Kim <riverful.kim@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>