Parse all the GPIO pins used by the DSI host and the display panel
along with its register ranges and store it in panel struct. This
avoids parsing the device-tree everytime during transitions between
trusted and primary vm.
Change-Id: Ibbb646358c0409703afda1c4f758f044fc8c0001
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>