Fix GPIO enable/disable operations which wrongly read the 0x0f register
to obtain the current mask of the enabled lines instead of using
the correct 0x0e register.

Also fix access to bit 0 of the register which is marked as reserved.

Fixes: 34009bff ("media: i2c: Add RDACM20 driver")
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>