netlabel: use GFP flags from caller instead of GFP_ATOMIC

This function takes a GFP flags as a parameter, but they are never used.
We don't take a lock in this function so there is no reason to prefer
GFP_ATOMIC over the caller's GFP flags.

There is only one caller, cipso_v4_map_cat_rng_ntoh(), and it passes
GFP_ATOMIC as the GFP flags so this doesn't change how the code works.
It's just a cleanup.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>