MIPS: Octeon: Fix compile error in arch/mips/cavium-octeon/flash_setup.c

The parse_mtd_partitions() and mtd_device_register() functions were
combined into mtd_device_parse_register().  So call that instead.

Signed-off-by: David Daney <david.daney@cavium.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2923/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>