compat-drivers: do not treat a warning as error

Older kernel version show more warnings like -Werror=unused-but-set-variable
and with this option they are treated as an error.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
compat-drivers: deactivate loopback testing for older kernels

ETH_TEST_FL_EXTERNAL_LB and ETH_TEST_FL_EXTERNAL_LB_DONE are not
available in kernel version < 3.1.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
compat-drivers: refresh alx patches

This was done against alx-20130124.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
compat-drivers: deactivate mac80211_hwsim for kernel < 2.6.31

kernel version < 2.6.31 does not support tasklet_hrtimer, so deactivate
the driver there.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
compat-drivers: use backport for second workqueue

bluetooth hci_core uses a second workqueue.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>