MIPS: init: Drop boot_mem_map

boot_mem_map was introduced very early and cannot handle memory maps
with nid. Nowadays, memblock can exactly replace boot_mem_map.

Detect pfn info and setup resources with memblock maps.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
[paul.burton@mips.com: Fix size calculation in check_kernel_sections_mem]
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