sdhci: Add sdhci support for spear devices

Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
Acked-by: Stefan Roese <sr@denx.de>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>