vfs_gpfs: add sys_proc_fd_path() fallback to vfs_gpfs_fset_dos_attributes()

vfs_gpfs: add sys_proc_fd_path() fallback to vfs_gpfs_fset_dos_attributes()

gpfs_set_winattrs() is a modifying operation, my expectation thus is that it is
not allowed on pathref (O_PATH) handles even though a recent Linux kernel commit
44a3b87444058b2cb055092cdebc63858707bf66 allowed calling utimensat() on pathref
handles.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14771
RN: Some VFS operations on pathref (O_PATH) handles fail on GPFS

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Christof Schmitt <cs@samba.org>
(cherry picked from commit 882a466ea5f45e5e2197f2408ccd560383e13c3f)