arm64: zynqmp: Disable EFI_CAPSULE_ON_DISK_EARLY

Sata/scsi and usb based devices are not started at this stage that's why
disks are not found and early update can't happen.
It is because of deficiency in the UEFI implementation which is not able to
deal with block devices which are added or removed after initialization.

EFI capsule on disk early feature needs to be fixed first to be able to
enable this feature properly.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>