sound: oss: mpu401.c: Cleaning up missing break in a case

Added a missed break in a case statement

This was found using a static code analysis program called cppcheck.
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/oss/mpu401.c

@@ -316,6 +316,7 @@ static int mpu_input_scanner(struct mpu_config *devc, unsigned char midic)
 				case 0xf6:
 					/* printk( "tune_request\n"); */
 					devc->m_state = ST_INIT;
+					break;
 
 					/*
 					 *    Real time messages