Add else all cases statement in case index is out of range

vendor/ess/lib/sis8300drvbcm.c

@@ -1726,6 +1726,9 @@ int sis8300drvbcm_get_calibration_sample(sis8300drv_usr *sisuser, unsigned int c
         calibration_sample_reg_offset = SIS8300BCM_ACCT_X_CALIBRATION_SAMPLE3_OFF; 
     } else if (index == 4) {
         calibration_sample_reg_offset = SIS8300BCM_ACCT_X_CALIBRATION_SAMPLE4_OFF; 
+    } else {
+        printf("%s: index %d is out of range (only 1 to 4 are accepted)\n", __func__, index);
+        return -1;
     }
     unsigned int reg = SIS8300BCM_CHANNEL_BLOCK_BASE + \
             (SIS8300BCM_CHANNEL_BLOCK_SIZE * channel) + \