[NETLABEL]: Move some initialization code into __init section.

Everything that is called from netlbl_init() can be marked with
__init. This moves 620 bytes from .text section to .text.init one.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>