[Beignet] [PATCH newRT] Add cl_gen_device_common.h file.

[Rebecca N. Palmer]

+#ifdef ENABLE_OPENCL_20
+.address_bits = 64,
+#else
+.address_bits = 32,
+#endif

Should that be 32 unconditionally, like it now is in master?
https://lists.freedesktop.org/archives/beignet/2017-February/008565.html