drm/rockchip/dsi: dw-mipi: correct the coding style

correct the coding style, according the checkpatch scripts

Signed-off-by: Chris Zhong <zyw@rock-chips.com>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1487577744-2855-4-git-send-email-zyw@rock-chips.com