net: filter: remove DL macro

Lets get rid of this macro. After commit 5bcfedf06f ("net: filter:
simplify label names from jump-table"), labels have become more
readable due to omission of BPF_ prefix but at the same time more
generic, so that things like `git grep -n` would not find them. As
a middle path, lets get rid of the DL macro as it's not strictly
needed and would otherwise just hide the full name.

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

include/linux/filter.h

@@ -37,9 +37,6 @@
 #define BPF_CALL	0x80	/* function call */
 #define BPF_EXIT	0x90	/* function return */
 
-/* Placeholder/dummy for 0 */
-#define BPF_0		0
-
 /* Register numbers */
 enum {
 	BPF_REG_0 = 0,