GitLab

As IPI mailbox service is common to both ZynqMP and Versal,
move it to xilinx/common.
Signed-off-by: Wendy Liang <wendy.liang@xilinx.com>
Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
Change-Id: I1a7008ccf7930829621147922d2c6d8d46df5502