media: exynos4-is: Simplify the pinctrl code

There is no need to request the "idle" pinctrl state in the driver as that
is implemented in the driver core and the pinctrl_pm_* API can be used for
switching between the default and the idle state.

Simplify the pinctrl code to only request and check for the mandatory
"default" pinctrl state.

Switching between the default/idle pinctrl state is not yet implemented
in the driver and this patch doesn't change that.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>