ARM: SAMSUNG: Fix missing api-change from subsys_interface change

Commit 4a858cfc (arm: convert sysdev_class to a regular subsystem)
converted the samsung sysdevs into subsys_interface instances.

While the original add-function only had a (struct sys_device *)
parameter, the dev_add from subsys_interface needs
	(struct device *, struct subsys_interface *)
leading to "initialized from incompatible pointer type" warnings.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>