mtd: rawnand: lpc32xx_slc: fix GPIO descriptor leak on probe error and remove

mtd: rawnand: lpc32xx_slc: fix GPIO descriptor leak on probe error and remove

The driver calls gpiod_get_optional() in the probe function but
never calls gpiod_put() in the remove function or in the probe
error path. This leads to a GPIO descriptor resource leak.
The lpc32xx_mlc.c driver in the same directory handles this
correctly by calling gpiod_put() on both paths.

Add gpiod_put() in the remove function and in the probe error path
to fix the resource leak.

Fixes: 6b923db2867c ("mtd: rawnand: lpc32xx_slc: switch to using gpiod API")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>