input: touchscreen: add multiple config data support for GT9xx

Goodix GT9xx touchscreen driver supports up to six groups of config
data and uses hardware GPIO configuration to select which one will
be used. This change allows these six config groups to be loaded
from devicetree.

Change-Id: I9dfd698e7084164688dd964ed914d5eecc75ecd3
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>