ARM: 6675/1: use phys_addr_t instead of unsigned long in conversion code

The unsigned long datatype is not sufficient for mapping physical addresses
>= 4GB.

This patch ensures that the address conversion code in asm/memory.h casts
to the correct type when handling physical addresses. The internal v2p
macros only deal with lowmem addresses, so these do not need to be modified.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>