opencl: Force the use of 1.2 APIs

Silences warnings regarding `clCreateCommandQueue` being deprecated.

Only a very limited number of products support 2.0. Since the
replacement API (`clCreateCommandQueueWithProperties`) is only available
in 2.0, we should not update it just yet.

libavutil/opencl.h

@@ -32,6 +32,7 @@
 #ifndef LIBAVUTIL_OPENCL_H
 #define LIBAVUTIL_OPENCL_H
 
+#define CL_USE_DEPRECATED_OPENCL_1_2_APIS 1
 #ifdef __APPLE__
 #include <OpenCL/cl.h>
 #else