Use Format_isValid() and Format_isEqual() instead of direct comparison

Change-Id: Ie87607aa514976947540a77775e6425c4e56e7d9
diff --git a/media/libnbaio/AudioBufferProviderSource.cpp b/media/libnbaio/AudioBufferProviderSource.cpp
index e952a00..4a69104 100644
--- a/media/libnbaio/AudioBufferProviderSource.cpp
+++ b/media/libnbaio/AudioBufferProviderSource.cpp
@@ -28,7 +28,7 @@
     NBAIO_Source(format), mProvider(provider), mConsumed(0)
 {
     ALOG_ASSERT(provider != NULL);
-    ALOG_ASSERT(format != Format_Invalid);
+    ALOG_ASSERT(Format_isValid(format));
 }
 
 AudioBufferProviderSource::~AudioBufferProviderSource()