bpftool: Strip const/volatile/restrict modifiers from .bss and .data vars

Similarly to .rodata, strip any const/volatile/restrict modifiers when
generating BPF skeleton. They are not helpful and actually just get in the way.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210507054119.270888-2-andrii@kernel.org

tools/bpf/bpftool/gen.c

@@ -106,8 +106,10 @@ static int codegen_datasec_def(struct bpf_object *obj,
 
 	if (strcmp(sec_name, ".data") == 0) {
 		sec_ident = "data";
+		strip_mods = true;
 	} else if (strcmp(sec_name, ".bss") == 0) {
 		sec_ident = "bss";
+		strip_mods = true;
 	} else if (strcmp(sec_name, ".rodata") == 0) {
 		sec_ident = "rodata";
 		strip_mods = true;