MIPS: BPF: Use BPF register names to describe the ABI

Use the BPF register names instead of the arch register names to
document how the ABI is structured.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: linux-kernel@vger.kernel.org
Patchwork: http://patchwork.linux-mips.org/patch/10529/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/net/bpf_jit.c

@@ -30,10 +30,10 @@
 
 /* ABI
  *
- * s3	BPF register A
- * s4	BPF register X
- * s5	*skb
- * s6	*scratch memory
+ * r_A		BPF register A
+ * r_X		BPF register X
+ * r_skb	*skb
+ * r_M		*scratch memory
  *
  * On entry (*bpf_func)(*skb, *filter)
  * a0 = MIPS_R_A0 = skb;