mm/memblock: introduce PHYS_ADDR_MAX

mm/memblock: introduce PHYS_ADDR_MAX

So far code was using ULLONG_MAX and type casting to obtain a
phys_addr_t with all bits set.  The typecast is necessary to silence
compiler warnings on 32-bit platforms.

Use the simpler but still type safe approach "~(phys_addr_t)0" to create a
preprocessor define for all bits set.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Stefan Agner <[email protected]>
Suggested-by: Linus Torvalds <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>