[PATCH] iio: chemical: sps30: mark expected switch fall-throughs

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warnings:

drivers/iio/chemical/sps30.c: In function ‘sps30_read_raw’:
drivers/iio/chemical/sps30.c:289:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
    switch (chan->channel2) {
    ^~~~~~
drivers/iio/chemical/sps30.c:299:3: note: here
   default:
   ^~~~~~~
drivers/iio/chemical/sps30.c: In function ‘sps30_do_cmd’:
drivers/iio/chemical/sps30.c:120:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
   buf[1] = (u8)SPS30_AUTO_CLEANING_PERIOD;
          ^
drivers/iio/chemical/sps30.c:121:2: note: here
  case SPS30_READ_DATA_READY_FLAG:
  ^~~~
drivers/gpio/gpio-eic-sprd.c: In function ‘sprd_eic_irq_set_type’:
drivers/gpio/gpio-eic-sprd.c:403:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   switch (flow_type) {
   ^~~~~~
drivers/gpio/gpio-eic-sprd.c:435:2: note: here
  default:
  ^~~~~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/iio/chemical/sps30.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iio/chemical/sps30.c b/drivers/iio/chemical/sps30.c
index e03a28a67146..f308d8ddceec 100644
--- a/drivers/iio/chemical/sps30.c
+++ b/drivers/iio/chemical/sps30.c
@@ -118,6 +118,7 @@ static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size)
 	case SPS30_READ_AUTO_CLEANING_PERIOD:
 		buf[0] = SPS30_AUTO_CLEANING_PERIOD >> 8;
 		buf[1] = (u8)SPS30_AUTO_CLEANING_PERIOD;
+		/* fall through */
 	case SPS30_READ_DATA_READY_FLAG:
 	case SPS30_READ_DATA:
 	case SPS30_READ_SERIAL:
@@ -296,6 +297,7 @@ static int sps30_read_raw(struct iio_dev *indio_dev,
 
 				return IIO_VAL_INT_PLUS_MICRO;
 			}
+			/* fall through */
 		default:
 			return -EINVAL;
 		}
-- 
2.20.1