staging: brcm80211: made overlapping WMM functions more similar

Code cleanup. Functions wlc_edcf_setparams() and
wlc_wme_setparams() duplicate code amongst each other. This commit
attempts to make life easier for the reviewer, by introducing non
functional changes that bring wlc_edcf_setparams() more in line
with wlc_wme_setparams(). As a result the subsequent commit can be
reviewed more easily.

Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>