drivers: kscan: fix GT911 support when not using interrupt

Fix support for GT911 touchscreen driver when not using interrupt.
The controller still requires that the INT pin be set to input in
order to correctly respond to I2C queries.

Also, the GT911 requires that the INT pin is not configured until the
RESET pin has been low at least 10 ms after reset, so add an additional
delay during initialization to account for this.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>