RISC-V: Fix usage of memblock_enforce_memory_limit

RISC-V: Fix usage of memblock_enforce_memory_limit

memblock_enforce_memory_limit accepts the maximum memory size not the
maximum address that can be handled by kernel. Fix the function invocation
accordingly.

Fixes: 1bd14a66ee52 ("RISC-V: Remove any memblock representing unusable memory area")
Cc: [email protected]
Reported-by: Bin Meng <[email protected]>
Tested-by: Bin Meng <[email protected]>
Acked-by: Mike Rapoport <[email protected]>
Signed-off-by: Atish Patra <[email protected]>
Signed-off-by: Palmer Dabbelt <[email protected]>