Added a missing break in optimc_read().

src/sound/snd_optimc.c

@@ -313,6 +313,7 @@ optimc_reg_read(uint16_t addr, void *p)
             case 3: /* MC4 */
             case 4: /* MC5 */
                 temp = optimc->regs[addr - 0xF8D];
+                break;
             case 5: /* MC6 */
                 temp = optimc->regs[5];
                 break;