media: rockchip: rga: fix clock cleanup

Fix this smatch warning:

drivers/media/platform/rockchip/rga/rga.c:734 rga_enable_clocks() warn: 'rga->sclk' from clk_prepare_enable() not released on lines: 734.

The reason is that aclk should be disabled/unprepared before
sclk, instead of the other way around.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Jacob Chen <jacob-chen@iotwrt.com>
Cc: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>