mips: Manually call fdt_init_reserved_mem() method

Since memblock-patchset was introduced the reserved-memory nodes are
supported being declared in dt-files. So these nodes are actually parsed
during the arch setup procedure when the early_init_fdt_scan_reserved_mem()
method is called. But due to the arch-specific boot mem_map container
utilization we need to manually call the fdt_init_reserved_mem() method
after all the available and reserved memory has been moved to memblock.
The first function call performed before bootmem_init() by the
early_init_fdt_scan_reserved_mem() routine fails due to the lack of any
memblock memory regions to allocate from at that stage.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Serge Semin <Sergey.Semin@t-platforms.ru>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org