phy: Add drivers for PCIe and SATA phy on SPEAr13xx

ARM based ST Microelectronics's SPEAr1310/40 platforms uses ST's phy (known as
'miphy') for PCIe and SATA. This patch adds drivers for these miphys.

This also adds proper bindings for miphys.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pratyush Anand <pratyush.anand@st.com>
Tested-by: Mohit Kumar <mohit.kumar@st.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
[viresh: fixed logs/cclist/checkpatch warnings, broken into smaller patches]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>