fix sti-netlink.c compilation failure

Fix this compilation error in current linux-omap-2.6 git head:

  CC      arch/arm/plat-omap/sti/sti-netlink.o
arch/arm/plat-omap/sti/sti-netlink.c: In function 'sti_netlink_init':
arch/arm/plat-omap/sti/sti-netlink.c:145: warning: passing argument 4 of 'netlink_kernel_create' from incompatible pointer type
arch/arm/plat-omap/sti/sti-netlink.c:145: error: too few arguments to function 'netlink_kernel_create'
make[2]: *** [arch/arm/plat-omap/sti/sti-netlink.o] Error 1
make[1]: *** [arch/arm/plat-omap/sti] Error 2
make: *** [arch/arm/plat-omap] Error 2

Compile-tested only.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>