ASoC: ti: Mark expected switch fall-throughs

Mark switch cases where we are expecting to fall through.

This patch fixes the following warning (Building: arm):

sound/soc/ti/n810.c: In function ‘n810_ext_control’:
sound/soc/ti/n810.c:48:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
line1l = 1;
~~~~~~~^~~
sound/soc/ti/n810.c:49:2: note: here
case N810_JACK_HP:
^~~~

sound/soc/ti/rx51.c: In function ‘rx51_ext_control’:
sound/soc/ti/rx51.c:57:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
hs = 1;
~~~^~~
sound/soc/ti/rx51.c:58:2: note: here
case RX51_JACK_HP:
^~~~

Signed-off-by: Gustavo A. R. Silva <[e-mail]>
Acked-by: Jarkko Nikula <[e-mail]>
Link: https://lore.kernel.org/r/20190729221534.GA18696@embeddedor
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/ti/n810.c

···
 	switch (n810_jack_func) {
 	case N810_JACK_HS:
 		line1l = 1;
+		/* fall through */
 	case N810_JACK_HP:
 		hp = 1;
 		break;

sound/soc/ti/rx51.c

···
 		break;
 	case RX51_JACK_HS:
 		hs = 1;
+		/* fall through */
 	case RX51_JACK_HP:
 		hp = 1;
 		break;