ALSA: sb8: Fix fall-through annotations

Replace "fallthru" with a proper "fall through" annotation.

This fix is part of the ongoing efforts to enabling
-Wimplicit-fallthrough

Signed-off-by: Gustavo A. R. Silva <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>

sound/isa/sb/sb8_main.c

···
 			chip->playback_format = SB_DSP_HI_OUTPUT_AUTO;
 			break;
 		}
-		/* fallthru */
+		/* fall through */
 	case SB_HW_201:
 		if (rate > 23000) {
 			chip->playback_format = SB_DSP_HI_OUTPUT_AUTO;
 			break;
 		}
-		/* fallthru */
+		/* fall through */
 	case SB_HW_20:
 		chip->playback_format = SB_DSP_LO_OUTPUT_AUTO;
 		break;
···
 			chip->capture_format = SB_DSP_HI_INPUT_AUTO;
 			break;
 		}
-		/* fallthru */
+		/* fall through */
 	case SB_HW_20:
 		chip->capture_format = SB_DSP_LO_INPUT_AUTO;
 		break;
···
 	case SB_MODE_PLAYBACK_16:	/* ok.. playback is active */
 		if (chip->hardware != SB_HW_JAZZ16)
 			break;
-		/* fallthru */
+		/* fall through */
 	case SB_MODE_PLAYBACK_8:
 		substream = chip->playback_substream;
 		if (chip->playback_format == SB_DSP_OUTPUT)
···
 	case SB_MODE_CAPTURE_16:
 		if (chip->hardware != SB_HW_JAZZ16)
 			break;
-		/* fallthru */
+		/* fall through */
 	case SB_MODE_CAPTURE_8:
 		substream = chip->capture_substream;
 		if (chip->capture_format == SB_DSP_INPUT)