brcm47xx: improve IRQ handling for bcma based devices

This was party inspirited by patches send by Nathan Hintz <nlhintz@hotmail.com>


git-svn-id: svn://svn.openwrt.org/openwrt@34989 3c298f89-4303-0410-b956-a3cf2f4a3e73
brcm47xx: BCMA - IRQ Update - Fix IRQ Flag for I2S Core

Adjust the IRQ Flag value from 8 to 7 for I2S Core for BCM4716 and
BCM4748 (per the Broadcom SDK).  IRQ Flag values greater than 7 are
ignored when setting the interrupt masks.

Signed-off-by: Nathan Hintz <nlhintz@hotmail.com>


git-svn-id: svn://svn.openwrt.org/openwrt@34990 3c298f89-4303-0410-b956-a3cf2f4a3e73