We currently support only panels connected to dsi output. We're going to
also support external bridge chips now.

Change 'panel_node' to 'device_node' in the struct msm_dsi_host and
'panel_flags' to 'device_flags' in msm_dsi. This makes things sound a
bit more generic.
Signed-off-by: NArchit Taneja <architt@codeaurora.org>
Signed-off-by: NRob Clark <robdclark@gmail.com>