OMAPDSS: tpo-td043 panel: handle gpios in panel driver

The tpo-td043mtea1 panel driver leaves gpio configurations to the
platform_enable and disable calls in the platform's board file. These should
happen in the panel driver itself.

Create a platform data struct for the panel, this contains the reset gpio
number used by the panel driver, this struct will be passed to the panel driver
as platform data. The driver will request and configure the reset gpio rather
than leaving it to platform callbacks in board files.

This will help in removing the need for the panel drivers to have platform
related callbacks.

Signed-off-by: Archit Taneja <archit@ti.com>