Revert "Updated Linux Firmware to latest"

This reverts commit 39a9467e4b0b2909e5140cb7f45dcd0038220067.
Merge branch 'PeterDaveHello-fix_linux_firmware'
upgrade kernel from 3.15.6 to 3.15.7
upgrade kernel from 3.15.7 to 3.15.8
Merge branch 'upgrade_kernel' of https://github.com/PeterDaveHello/foldingathome into PeterDaveHello-upgrade_kernel
Updated kernel configuration for new options in 3.15.8
Merge branch 'PeterDaveHello-upgrade_kernel'