RISC-V: Fix memblock_free() usages in init_resources()

`memblock_free()` takes a physical address as its first argument.
Fix the wrong usages in `init_resources()`.

Fixes: ffe0e526 ("RISC-V: Improve init_resources()")
Fixes: 797f0375

 ("RISC-V: Do not allocate memblock while iterating reserved memblocks")
Signed-off-by: Wende Tan <twd2.me@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>