input: touchscreen: bu21150: add support for more features

JDI BU21150 touch analog front end(TAFE) provides an incell touch panel.
The driver supports a variety of panels ranging from 5-inch, 6-inch, and
5.5-inch. Different panels may have different sensor line mapping and
DDIC circuits. Add features below to achieve heterogeneous panel support.

Features included in this patch:
 - Add DDIC GPIO support
 - Add module enable GPIO support
 - correct optional pinctrl attributes probing
 - updated power on reset sequence

Change-Id: I0901a625987d370f8fd9678ad675d816e174b3ca
Signed-off-by: Chun Zhang <chunz@codeaurora.org>