drm/bridge/sii8620: Fix display of packed pixel modes

drm/bridge/sii8620: Fix display of packed pixel modes

[ Upstream commit fdddc65ab35d575b42aab411b2dc687601eab680 ]

Current implementation does not guarantee packed pixel modes working
with every dongle. There are some dongles, which require selecting
the output mode explicitly.

Write proper values to registers in packed_pixel mode, based on how it
is done in vendor's code. Select output color space: RGB
(no packed pixel) or YCBCR422 (packed pixel).

This reverts commit e8b92efa629dac0e70ea4145c5e70616de5f89c8
("drm/bridge/sii8620: fix display of packed pixel modes in MHL2").

Signed-off-by: Maciej Purski <m.purski@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1530204243-6370-3-git-send-email-m.purski@samsung.com
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>