netlabel: fix shift wrapping bug in netlbl_catmap_setlong()

There is a shift wrapping bug in this code on 32-bit architectures.
NETLBL_CATMAP_MAPTYPE is u64, bitmap is unsigned long.
Every second 32-bit word of catmap becomes corrupted.

Signed-off-by: Dmitry Mastykin <dmastykin@astralinux.ru>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>