net: filter: rename sk_chk_filter() -> bpf_check_classic()

trivial rename to indicate that this functions performs classic BPF checking

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

Documentation/networking/filter.txt

@@ -591,7 +591,7 @@ sk_unattached_filter_destroy() for destroying it. The macro
 SK_RUN_FILTER(filter, ctx) transparently invokes eBPF interpreter or JITed
 code to run the filter. 'filter' is a pointer to struct sk_filter that we
 got from sk_unattached_filter_create(), and 'ctx' the given context (e.g.
-skb pointer). All constraints and restrictions from sk_chk_filter() apply
+skb pointer). All constraints and restrictions from bpf_check_classic() apply
 before a conversion to the new layout is being done behind the scenes!
 
 Currently, the classic BPF format is being used for JITing on most of the