bpf: remove reference to sock_filter_ext from kerneldoc comment

struct sock_filter_ext didn't make it into the tree and is now called
struct bpf_insn. Reword the kerneldoc comment for bpf_convert_filter()
accordingly.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/filter.c

@@ -354,7 +354,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
  *	@new_prog: buffer where converted program will be stored
  *	@new_len: pointer to store length of converted program
  *
- * Remap 'sock_filter' style BPF instruction set to 'sock_filter_ext' style.
+ * Remap 'sock_filter' style classic BPF (cBPF) instruction set to 'bpf_insn'
+ * style extended BPF (eBPF).
  * Conversion workflow:
  *
  * 1) First pass for calculating the new program length: