soc: xilinx: zynqmp: Add soc_xilinx_zynqmp driver

soc: xilinx: zynqmp: Add soc_xilinx_zynqmp driver

soc_xilinx_zynqmp driver allows identification of family & revision
of zynqmp SoC. This driver is selected by CONFIG_SOC_XILINX_ZYNQMP.
Add this config to xilinx_zynqmp_virt_defconfig file.
Probe this driver using platdata U_BOOT_DEVICE structure which is
specified in mach-zynqmp/cpu.c.

Signed-off-by: T Karthik Reddy <[email protected]>
Reviewed-by: Ashok Reddy Soma <[email protected]>
Signed-off-by: Michal Simek <[email protected]>