ASoC: wm8994: Fix missing break in switch

commit ad0eaee6195db1db1749dd46b9e6f4466793d178 upstream.

Add missing break statement in order to prevent the code from falling
through to the default case.

Addresses-Coverity-ID: 115050 ("Missing break in switch")
Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
[Gustavo: Backported to 3.16..4.18 - Remove code comment removal]
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>