media: ov5640: fix framerate update

Changing framerate right before streamon had no effect,
the new framerate value was taken into account only at
next streamon, fix this.

Signed-off-by: Hugues Fruchet <hugues.fruchet@st.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>