drm/bridge: lt9611: Fix handling of 4k panels

stable inclusion
from stable-5.10.68
commit 575279059e26b27aababbb7edae2f0f19205779d
bugzilla: 182671 https://gitee.com/openeuler/kernel/issues/I4EWUH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=575279059e26b27aababbb7edae2f0f19205779d



--------------------------------

commit d1a97648 upstream.

4k requires two dsi pipes, so don't report MODE_OK when only a
single pipe is configured. But rather report MODE_PANEL to
signal that requirements of the panel are not being met.

Reported-by: Peter Collingbourne <pcc@google.com>
Suggested-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Tested-by: Anibal Limon <anibal.limon@linaro.org>
Tested-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201217140933.1133969-1-robert.foss@linaro.org


Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>