bcmdhd: allow only unicast packets when screen is off

    It seems HTC uses an ioctl instead of the packet filter to block broadcast a
    multicast packets but this does not work with the latest firmware.

    Bring back dhd_set_packet_filter.

    Kernel wakelock wlan_rx_wake overnight:
    Before: 40mins
    After: 3 mins
Update kernel config.
Enables a high-brightness mode for the flash LED.
Clean up the kernel source, prepare for .gitignore.