[media] exynos4-is: Fix regulator/gpio resource releasing on the driver removal

Remove regulator_bulk_free() calls as devm_regulator_bulk_get() function
is used to get the regulators so those will be freed automatically while
the driver is removed.
Missing gpio free is fixed by requesting a gpio with the devm_* API.
All that is done now in the I2C client driver remove() callback is the
media entity cleanup call.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>