SPEAr : Support added for SPEAr320 board

SPEAr320 SoC support contains basic spear320 support along with the
usage of following drivers
- serial driver(UART)
- i2c driver
- smi driver
- nand driver(FSMC)
- usbd driver
- emi driver(cfi support)

Signed-off-by: Vipin <vipin.kumar@st.com>