xdp: Handle frame_sz in xdp_convert_zc_to_xdp_frame()

In commit 34cc0b3 we only handled the frame_sz in convert_to_xdp_frame().
This patch will also handle frame_sz in xdp_convert_zc_to_xdp_frame().

Fixes: 34cc0b3 ("xdp: Xdp_frame add member frame_sz and handle in convert_to_xdp_frame")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200616103518.2963410-1-liuhangbin@gmail.com

net/core/xdp.c

@@ -462,6 +462,7 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp)
 	xdpf->len = totsize - metasize;
 	xdpf->headroom = 0;
 	xdpf->metasize = metasize;
+	xdpf->frame_sz = PAGE_SIZE;
 	xdpf->mem.type = MEM_TYPE_PAGE_ORDER0;
 
 	xsk_buff_free(xdp);