Make double-open radio tuner failure more verbose.

Bug: b/36863239
Test: manual (watching logs)
Change-Id: I032349eaa11b4a8008f09113c3898452572db219
diff --git a/modules/radio/radio_hw.c b/modules/radio/radio_hw.c
index 456c866..a7dee75 100644
--- a/modules/radio/radio_hw.c
+++ b/modules/radio/radio_hw.c
@@ -660,6 +660,7 @@
     pthread_mutex_lock(&rdev->lock);
 
     if (rdev->tuner != NULL) {
+        ALOGE("Can't open tuner twice");
         status = -ENOSYS;
         goto exit;
     }