mach-k3: add reserved memory fixups for next boot stage

mach-k3: add reserved memory fixups for next boot stage

The boot flow in K3 platforms requires the subsequent boot stages to be
aware of the memory reserved for previous boot binaries. In the regular
boot sequence of:

R5 SPL -> ATF -> OP-TEE -> A-core SPL -> U-Boot -> Kernel,

Both A-core SPL and U-Boot should be made aware of the memory reserved
for ATF and OP-TEE from their device-tree. Currently this information is
absent.

Therefore this patch adds the reserved-memory regions as part of
spl_perform_arch_fixups for the next stage's DT. This is called during
both R5 and A-core SPL which fixes up the DT for their respective next
stages: A-core SPL and U-Boot proper.

Reviewed-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Anshul Dalal <anshuld@ti.com>
Tested-by: Wadim Egorov <w.egorov@phytec.de>