chore(xilinx): replace fsbl with xbl

The handoff functionality is common between platforms and all
platforms do not use fsbl terminology. Renaming handoff related code
to generic naming.

Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
Change-Id: Ic250af927f33c4fecbc2e6bab01b83a6dd2aab52
Signed-off-by: Akshay Belsare <akshay.belsare@amd.com>
4 files changed