drivers: kscan: gt911: ignore touch events if TOUCH_STATUS mask is clear

Ignore touch events from GT911 IC when TOUCH_STATUS_MSK bit is not set
in status register. This resolves an error where the GT911 driver would
report a touch event end directly after a touch occured, as the touch
status register would be 0x0, which the driver incorrectly interpreted
as a touch release.

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