ARM: dts: enable ahci sata and sata phy for exynos5250

This patch adds dt entry for ahci sata controller and its
corresponding phy controller.phy node has been added w.r.t
new generic phy framework.

Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@samsung.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>