MIPS: Octeon: mark GPIO controller node not populated after IRQ init.

MIPS: Octeon: mark GPIO controller node not populated after IRQ init.

We clear the OF_POPULATED flag for the GPIO controller node on Octeon
processors. Otherwise, none of the devices hanging on the GPIO lines
are probed. The 'gpio-leds' driver on OCTEON failed to probe in addition
to other devices on Cavium 71xx and 78xx development boards.

Fixes: 2562ee36e0fb ("of/irq: Mark initialised interrupt controllers as populated")
Signed-off-by: Steven J. Hill <steven.hill@cavium.com>
Tested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: David Daney <david.daney@cavium.com>
Cc: Rob Herring <robh@kernel.org>
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14091/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>