MIPS: mm: Drop boot_mem_map

Initialize maar by resource map and replace page_is_ram
by memblock_is_memory.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
[paul.burton@mips.com:
  - Fix bad MAAR address calculations.
  - Use ALIGN() & define maar_align to make it clearer what's going on
    with address manipulations.
  - Drop the new used field from struct maar_config.
  - Rework the RAM walk to avoid iterating over the cfg array needlessly
    to find the first unused entry, then count used entries at the end.
    Instead just keep the count as we go.]
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: yasha.che3@gmail.com
Cc: aurelien@aurel32.net
Cc: sfr@canb.auug.org.au
Cc: fancer.lancer@gmail.com
Cc: matt.redfearn@mips.com
Cc: chenhc@lemote.com