hwc/overlay/hdmi: Fix / enable some error messages.

Fix cases where some errors are really warnings/info.
Print one-time events like HDMI connect disconnect as info logs.
Print the error string and type on MSMFB_OVERLAY_PREPARE failure.

An ENODEV from driver corresponds to a pipe not available and should
be treated as a warning. This could happen if a previous UNSET is
pending due to a missed vsync. ENODEV should be treated as fatal
only if it is seen continuously representing a book-keeping
blunder.

Change-Id: I730d4ac7db84c287f47805b9c74792c90cfadc6c
diff --git a/libhwcomposer/hwc_copybit.cpp b/libhwcomposer/hwc_copybit.cpp
index 38c0810..546a67b 100644
--- a/libhwcomposer/hwc_copybit.cpp
+++ b/libhwcomposer/hwc_copybit.cpp
@@ -216,8 +216,13 @@
         return false;
     }
 
-    if (mEngine == NULL || !(validateParams(ctx, list))) {
-        ALOGE("%s: Invalid Params", __FUNCTION__);
+    if (mEngine == NULL) {
+        ALOGW("%s: Copybit HAL not enabled", __FUNCTION__);
+        return false;
+    }
+
+    if (!(validateParams(ctx, list))) {
+        ALOGE("%s: validateParams() failed", __FUNCTION__);
         return false;
     }
     PtorInfo* ptorInfo = &(ctx->mPtorInfo);