sparc: bpf_jit: add SKF_AD_PKTTYPE support to JIT

commit 233577a2 ("net: filter: constify detection of pkt_type_offset")
allows us to implement simple PKTTYPE support in sparc JIT

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>