Input: resistive-adc-touch - struct headers should start with 'struct <name>'

Fixes the following W=1 kernel build warning(s):

 drivers/input/touchscreen/resistive-adc-touch.c:34: warning: cannot understand function prototype: 'struct grts_state '
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20201104162427.2984742-10-lee.jones@linaro.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/resistive-adc-touch.c

@@ -23,7 +23,7 @@
 #define GRTS_MAX_POS_MASK				GENMASK(11, 0)
 
 /**
- * grts_state - generic resistive touch screen information struct
+ * struct grts_state - generic resistive touch screen information struct
  * @pressure_min:	number representing the minimum for the pressure
  * @pressure:		are we getting pressure info or not
  * @iio_chans:		list of channels acquired