selftests/bpf: Adjust btf_dump test to reflect recent change in file_operations

The btf_dump test fails:

test_btf_dump_struct_data:FAIL:file_operations unexpected file_operations: actual '(struct file_operations){
	.owner = (struct module *)0xffffffffffffffff,
	.fop_flags = (fop_flags_t)4294967295,
	.llseek = (loff_t (*)(struct f' != expected '(struct file_operations){
	.owner = (struct module *)0xffffffffffffffff,
	.llseek = (loff_t (*)(struct file *, loff_t, int))0xffffffffffffffff,'

The "fop_flags" is a recent addition to the struct file_operations in
commit 210a03c9 ("fs: claw back a few FMODE_* bits")

This patch changes the test_btf_dump_struct_data() to reflect
this change.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20240516164310.2481460-1-martin.lau@linux.dev

tools/testing/selftests/bpf/prog_tests/btf_dump.c

@@ -653,7 +653,7 @@ static void test_btf_dump_struct_data(struct btf *btf, struct btf_dump *d,
 		cmpstr =
 "(struct file_operations){\n"
 "	.owner = (struct module *)0xffffffffffffffff,\n"
-"	.llseek = (loff_t (*)(struct file *, loff_t, int))0xffffffffffffffff,";
+"	.fop_flags = (fop_flags_t)4294967295,";
 
 		ASSERT_STRNEQ(str, cmpstr, strlen(cmpstr), "file_operations");
 	}