A few places in the code (mac80211 and iwlmvm) use the same
TU_TO_JIFFIES() macro and could use TU_TO_EXP_TIME() that
mac80211 has. Make these available to everyone and use them.
Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>