MIPS: ath79: Use correct IRQ number for the OHCI controller on AR7240

The currently assigned IRQ number to the OHCI controller is incorrect for
the AR7240 SoC, and that leads to the following error message from the
OHCI driver:

ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
ath79-ohci ath79-ohci: Atheros built-in OHCI controller
ath79-ohci ath79-ohci: new USB bus registered, assigned bus number 1
ath79-ohci ath79-ohci: irq 14, io mem 0x1b000000
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 1 port detected
usb 1-1: new full-speed USB device number 2 using ath79-ohci
ath79-ohci ath79-ohci: Unlink after no-IRQ?  Controller is probably using the wrong IRQ.

Fix this by using the correct IRQ number.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4168/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>