vtenc: should support GLMemory
Submitted by Nick Kallen
Currently vtenc caps disallow GLMemory. However, having tested this on iOS and reviewed the code, it actually works using GLMemory. Since the underlying pixel buffer is always a core media buffer,
pbuf = gst_core_media_buffer_get_pixel_buffer (frame->input_buffer);
this statement is valid whether the input_buffer's pixel buffer is GL buffer or not.
Therefore, just changing the static caps works.