arm64: zynqmp: Define a way to intialize TCM

TCM on ZynqMP needs to be intialized in a sequence
and this patch provides a global routine to perform
this as per requirement.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>