Ported change I080542f3211c786c92bc495cc9c72576147fe6a6

A recent refactor is filling /var/log/Xorg.0.log with debug messages on
every input sample, and labeling them as errors.  Reduce these messages
to LOG_DEBUG.
Note: "SYN_DROPPED" and "SYN_UNKNOWN" are anomalous conditions that we do
want to report as a WARNING.

Also reduce a few other recoverable error conditions to WARNING.

BUG=chromium-os:31880
TEST=tail -F /var/log/Xorg.0.log, no more Event_Print() message

Change-Id: Ia33aa6dc7c5fdbc558f5efa0d15049ff222df4c6
diff --git a/src/libevdev_event.c b/src/libevdev_event.c
index feb43ca..3050e53 100644
--- a/src/libevdev_event.c
+++ b/src/libevdev_event.c
@@ -391,11 +391,11 @@
                 ev->time.tv_sec, ev->time.tv_usec);
             return;
         case SYN_DROPPED:
-            LOG_DEBUG(device, "@ %ld.%06ld  ++++++++ SYN_DROPPED ++++++++\n",
+            LOG_WARNING(device, "@ %ld.%06ld  ++++++++ SYN_DROPPED ++++++++\n",
                 ev->time.tv_sec, ev->time.tv_usec);
             return;
         default:
-            LOG_DEBUG(device, "@ %ld.%06ld  ?????? SYN_UNKNOWN (%d) ?????\n",
+            LOG_WARNING(device, "@ %ld.%06ld  ?????? SYN_UNKNOWN (%d) ?????\n",
                 ev->time.tv_sec, ev->time.tv_usec, ev->code);
             return;
         }
@@ -555,7 +555,7 @@
     MtSlotPtr slot = evstate->slot_current;
 
     if (axis == NULL) {
-        LOG_ERROR(device, "ABS_MT[%02x] was not reported by this device\n",
+        LOG_WARNING(device, "ABS_MT[%02x] was not reported by this device\n",
                   ev->code);
         return;
     }
@@ -569,7 +569,7 @@
     }
 
     if (slot == NULL) {
-        LOG_ERROR(device, "MT slot not set. Ignoring ABS_MT event\n");
+        LOG_WARNING(device, "MT slot not set. Ignoring ABS_MT event\n");
         return;
     }