ARM: 7863/1: Let arm_add_memory() always use 64-bit arguments

The DTB and/or the kernel command line may pass
64-bit addresses regardless of kernel configuration,
so update arm_add_memory() to take 64-bit arguments
independently of the phys_addr_t size.

This allows non-wrapping handling of high memory
banks such as the second memory bank of APE6EVM
(at 0x2_0000_0000) in case of 32-bit phys_addr_t.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>