mach-k3: fix reading size and addr from fdt on R5

mach-k3: fix reading size and addr from fdt on R5

fdtdec_get_addr_size uses architecture dependent datatypes which causes
the 32-bit R5 to fail when reading the 64-bit size and addr fields of
reg nodes from the fdt.

Therefore change it to a common api for both 64 and 32 bit platforms to
allow for fdt fixups from R5.

Fixes: 8b0fc29de0e3 ("arm: mach-k3: am62: Fixup TF-A/OP-TEE reserved-memory node in FDT")
Signed-off-by: Anshul Dalal <anshuld@ti.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>