Input: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200707180857.GA30600@embeddedor
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/tablet/gtco.c

@@ -676,8 +676,8 @@ static void gtco_urb_callback(struct urb *urbinfo)
 
 			/* Mask out the Y tilt value used for pressure */
 			device->buffer[7] = (u8)((device->buffer[7]) & 0x7F);
+			fallthrough;
 
-			/* Fall thru */
 		case 4:
 			/* Tilt */
 			input_report_abs(inputdev, ABS_TILT_X,
@@ -685,8 +685,8 @@ static void gtco_urb_callback(struct urb *urbinfo)
 
 			input_report_abs(inputdev, ABS_TILT_Y,
 					 sign_extend32(device->buffer[7], 6));
+			fallthrough;
 
-			/* Fall thru */
 		case 2:
 		case 3:
 			/* Convert buttons, only 5 bits possible */
@@ -695,8 +695,8 @@ static void gtco_urb_callback(struct urb *urbinfo)
 			/* We don't apply any meaning to the bitmask,
 			   just report */
 			input_event(inputdev, EV_MSC, MSC_SERIAL, val);
+			fallthrough;
 
-			/*  Fall thru */
 		case 1:
 			/* All reports have X and Y coords in the same place */
 			val = get_unaligned_le16(&device->buffer[1]);

drivers/input/tablet/pegasus_notetaker.c

@@ -146,7 +146,7 @@ static void pegasus_parse_packet(struct pegasus *pegasus)
 	/* xy data */
 	case BATTERY_LOW:
 		dev_warn_once(&dev->dev, "Pen battery low\n");
-		/* fall through */
+		fallthrough;
 
 	case BATTERY_NO_REPORT:
 	case BATTERY_GOOD: