LoongArch: Call early_init_fdt_scan_reserved_mem() earlier

The unflatten_and_copy_device_tree() function contains a call to
memblock_alloc(). This means that memblock is allocating memory before
any of the reserved memory regions are set aside in the arch_mem_init()
function which calls early_init_fdt_scan_reserved_mem(). Therefore,
there is a possibility for memblock to allocate from any of the
reserved memory regions.

Hence, move the call to early_init_fdt_scan_reserved_mem() to be earlier
in the init sequence, so that the reserved memory regions are set aside
before any allocations are done using memblock.

Cc: stable@vger.kernel.org
Fixes: 88d4d957

 ("LoongArch: Add FDT booting support from efi system table")
Signed-off-by: Oreoluwa Babatunde <quic_obabatun@quicinc.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>