arm64: versal: Enable support for Gigadevice/ISSI flashes

Enable support for Gigadevice/ISSI flash parts for Versal platform.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>