video: rockchip: rk322x: use htotal to adjust fps

video: rockchip: rk322x: use htotal to adjust fps

Use dclk to adjust fps may effect many things, some display
controller also need to know dclk update, such as mipi.
So if we change fps by dclk, we need update mipi or other
display controller, it waste time and screen would flash

From the fps formula: fps = dclk / htotal * vtotal

Instead change dclk, we also can modify fps by htotal or vtotal.

On testing, vtotal would effect display, use htotal is more safe.

Change-Id: I67d58a815eae150b4e6390b6608557b87d43a27b
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>