drm: Stop building the mach64 driver

It doesn't compile anymore with some drm changes from Linux 3.8.
wpa_supplicant(8): Fix struct ieee80211req_scan_result parsing in driver_bsd.c

* Since commit 32176cfd8803dac7f65c423373f231a378375c86 there is an
  additional isr_meshid_len field in struct ieee80211req_scan_result.
  We have to add this additional offset, when calculating the address
  of the IE data buffer.
kernel/vtnet: Replace recursion with a loop to avoid a stack overflow.