media: ov2680: Drop is_enabled flag

With runtime-pm it is guaranteed that ov2680_power_on() and
ov2680_power_off() will always be called in a balanced way;
and the is_enabled check in ov2680_s_ctrl() can be replaced
by checking the runtime-suspend state.

So there is no more need for the is_enabled flag, remove it.

While at it also make sure that flip control changes while
suspended still lead to the bayer-order getting updated so
that get_fmt returns the correct bayer-order.

Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>