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

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 210a03c9d51a ("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