media: s5c73m3: Switch to GPIO descriptors

The driver has an option to pass in GPIO numbers from platform
data but this is not used in the kernel so delete this. Get
GPIO descriptors using the standard API and simplify the code,
gpiolib will handle any inversions.

Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>