drm/hisilicon: Enforce 128-byte stride alignment to fix the hardware limitation

because the hardware limitation,The initial color depth must set to 32bpp
and must set the FB Offset of the display hardware to 128Byte alignment,
which is used to solve the display problem at 800x600 and 1440x900
resolution under 16bpp.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Gong junjie <gongjunjie2@huawei.com>
Acked-by: Xinliang Liu <xinliang.liu@linaro.org>
Signed-off-by: Xinliang Liu <xinliang.liu@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1583466184-7060-4-git-send-email-tiantao6@hisilicon.com