[media] mt9v032: Check return value of clk_prepare_enable/clk_set_rate

clk_set_rate(), clk_prepare_enable() functions can fail, so check the return
values to avoid surprises.

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>