MIPS: BMIPS: Improve BCM6368 device tree

- Remove unneeded leds0 alias.
- Switch to bcm6345-l1-intc interrupt controller.
- Use interrupt-controller instead of periph_intc and cpu_intc.
- Add uart1 node.
- Single ohci and ehci nodes.
- Avoid using underscores in node names.
- Rename uart aliases to serial.
- Remove blank line in cpus node.

[ralf@linux-mips.org: fix references in bcm96368mvwg.dts so the file keeps
building.]

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Cc: f.fainelli@gmail.com
Cc: jogo@openwrt.org
Cc: cernekee@gmail.com
Cc: robh@kernel.org
Cc: simon@fire.lp0.eu
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>