gpio: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-aspeed.c

@@ -411,13 +411,16 @@ static int aspeed_gpio_set_type(struct irq_data *d, unsigned int type)
 	switch (type & IRQ_TYPE_SENSE_MASK) {
 	case IRQ_TYPE_EDGE_BOTH:
 		type2 |= bit;
+		/* fall through */
 	case IRQ_TYPE_EDGE_RISING:
 		type0 |= bit;
+		/* fall through */
 	case IRQ_TYPE_EDGE_FALLING:
 		handler = handle_edge_irq;
 		break;
 	case IRQ_TYPE_LEVEL_HIGH:
 		type0 |= bit;
+		/* fall through */
 	case IRQ_TYPE_LEVEL_LOW:
 		type1 |= bit;
 		handler = handle_level_irq;

drivers/gpio/gpio-ath79.c

@@ -132,6 +132,7 @@ static int ath79_gpio_irq_set_type(struct irq_data *data,
 
 	case IRQ_TYPE_LEVEL_HIGH:
 		polarity |= mask;
+		/* fall through */
 	case IRQ_TYPE_LEVEL_LOW:
 		type |= mask;
 		break;

drivers/gpio/gpio-stmpe.c

@@ -299,7 +299,7 @@ static void stmpe_dbg_show_one(struct seq_file *s,
 			if (ret < 0)
 				return;
 			edge_det = !!(ret & mask);
-
+			/* fall through */
 		case STMPE1801:
 			rise_reg = stmpe->regs[STMPE_IDX_GPRER_LSB + bank];
 			fall_reg = stmpe->regs[STMPE_IDX_GPFER_LSB + bank];
@@ -312,7 +312,7 @@ static void stmpe_dbg_show_one(struct seq_file *s,
 			if (ret < 0)
 				return;
 			fall = !!(ret & mask);
-
+			/* fall through */
 		case STMPE801:
 		case STMPE1600:
 			irqen_reg = stmpe->regs[STMPE_IDX_IEGPIOR_LSB + bank];