mac80211: merge value scaling macros of minstrel_ht and minstrel

Both minstrel versions use individual ways to scale up integer values
to perform calculations. Merge minstrel_ht's scaling macros into
minstrels header file and use them in both minstrel versions.

Acked-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --cc net/mac80211/rc80211_minstrel.c
Simple merge

diff --cc net/mac80211/rc80211_minstrel.h
Simple merge

diff --cc net/mac80211/rc80211_minstrel_debugfs.c
Simple merge

diff --cc net/mac80211/rc80211_minstrel_ht.h
Simple merge