mm/memblock: add memblock memory allocation apis
Introduce memblock memory allocation APIs which allow to support PAE or LPAE extension on 32 bits archs where the physical memory start address can be beyond 4GB. In such cases, existing bootmem APIs which operate on 32 bit addresses won't work and needs memblock layer which operates on 64 bit addresses. So we add equivalent APIs so that we can replace usage of bootmem with memblock interfaces. Architectures already converted to NO_BOOTMEM use these new memblock interfaces. The architectures which are still not converted to NO_BOOTMEM continue to function as is because we still maintain the fal lback option of bootmem back-end supporting these new interfaces. So no functional change as such. In long run, once all the architectures moves to NO_BOOTMEM, we can get rid of bootmem layer completely. This is one step to remove the core code dependency with bootmem and also gives path for architectures to move away from bootmem. The proposed interface will became active if both CONFIG_HAVE_MEMBLOCK and CONFIG_NO_BOOTMEM are specified by arch. In case !CONFIG_NO_BOOTMEM, the memblock() wrappers will fallback to the existing bootmem apis so that arch's not converted to NO_BOOTMEM continue to work as is. The meaning of MEMBLOCK_ALLOC_ACCESSIBLE and MEMBLOCK_ALLOC_ANYWHERE is kept same. [akpm@linux-foundation.org: s/depricated/deprecated/] Signed-off-by:Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: