After the following patches,
commit de043da0b9 ("RISC-V: Fix usage of memblock_enforce_memory_limit")
commit 1bd14a66ee ("RISC-V: Remove any memblock representing unusable memory area")
commit b10d6bca87 ("arch, drivers: replace for_each_membock() with for_each_mem_range()")
some logic is useless, kill the mem_start/start/end and unneeded code.
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>