pci: Add PCIe driver for Samsung Exynos

Exynos5440 has a PCIe controller which can be used as Root Complex.
This driver supports a PCIe controller as Root Complex mode.

Signed-off-by: Surendranath Gurivireddy Balla <suren.reddy@samsung.com>
Signed-off-by: Siva Reddy Kallam <siva.kallam@samsung.com>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Cc: Pratyush Anand <pratyush.anand@st.com>
Cc: Mohit KUMAR <Mohit.KUMAR@st.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>