[PATCH] mac80211: Implementation of SIOCSIWRATE

The WEXT ioctl SIOCSIWRATE is not implemented in mac80211. This patch
adds the missing routine. It supports the 'auto' keyword, fixed rates,
and the combination of 'auto' and a fixed rate to select an upper bound.

Based on the patch from Mohamed Abbas <mabbas@linux.intel.com>.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>