ARM: 7465/1: Handle >4GB memory sizes in device tree and mem=size@start option

The memory regions which are passed to arm_add_memory() from
device tree blobs via early_init_dt_add_memory_arch() can
have sizes which are larger than will fit in a 32 bit integer,
so switch to using a phys_addr_t to hold them, to avoid
silently dropping the top 32 bits of the size. Similarly, use
phys_addr_t in early_mem() so that mem=size@start command line
options specifying more than 4GB behave sensibly.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>