basic: move BPF_JMP_A to override/linux/bpf_insn.h

Move the BPF_JMP_A macro from override/linux/bpf.h to
override/linux/bpf_insn.h. The bpf.h override conflicts with libbpf's
-I/usr/include/bpf/uapi include path. Since bpf_insn.h is not typically
installed at /usr/include/linux/ or /usr/include/bpf/uapi/linux/, the
override works without conflicts.

Fixes #40331

src/include/override/linux/bpf_insn.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include_next <linux/bpf.h>     /* IWYU pragma: export */
+#include_next <linux/bpf_insn.h>     /* IWYU pragma: export */
 
 /* defined in linux/filter.h */
 /* Unconditional jumps, goto pc + off16 */