Fixed KW issue 87954# for Libmix's IntelImageEncoder.

BZ: 161637

Issue: KW issue 87954# was reported, which might cause
buffer overflow.

Solution: Fixed it by adding buffer index's checking.

Change-Id: I44f25ab45daa580e1896fc5c8faac8de6b781176
Signed-off-by: SUN,Jing <jing.a.sun@intel.com>
diff --git a/imageencoder/ImageEncoder.cpp b/imageencoder/ImageEncoder.cpp
index d63ad5e..7427737 100644
--- a/imageencoder/ImageEncoder.cpp
+++ b/imageencoder/ImageEncoder.cpp
@@ -175,6 +175,10 @@
 			break;
 		}
 	}
+	if(INTEL_IMAGE_ENCODER_MAX_BUFFERS == i) {
+		LOGE("createSourceSurface: failed because the max surface count was reached!\n");
+		return VA_STATUS_ERROR_ALLOCATION_FAILED;
+	}
 
 	/* Allocate a source surface */
 	if (VA_RT_FORMAT_YUV420 == fourcc)