[media] exynos4-is: Clear isp-i2c adapter power.ignore_children flag

Since commit 04f59143
("i2c: let I2C masters ignore their children for PM")
the power.ignore_children flag is set when registering an I2C
adapter.  Since I2C transfers are not managed by the fimc-isp-i2c
driver its clients use pm_runtime_* calls directly to communicate
required power state of the bus controller.

However, when the power.ignore_children flag is set that doesn't
work, so clear that flag back after registering the adapter.
While at it drop pm_runtime_enable() call on the i2c_adapter
as it is already done by the I2C subsystem when registering
I2C adapter.

This patch is meant as a minimal change to fix the regression,
eventually the I2C_ISPx clock handling will be moved to the
top level fimc-is driver and whole runtime PM code is going to
be dropped from the fimc-is-i2c module.

Cc: <stable@vger.kernel.org> # 4.7+
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>