libfrog: pass mode to xfrog_file_setattr

libfrog: pass mode to xfrog_file_setattr

xfs/633 crashes rdump_fileattrs_path passes a NULL struct stat pointer
and then the fallback code dereferences it to get the file mode.
Instead, let's just pass the stat mode directly to it, because that's
the only piece of information that it needs.

Fixes: 128ac4dadbd633 ("xfs_db: use file_setattr to copy attributes on special files with rdump")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Andrey Albershteyn <aalbersh@kernel.org>