cfg80211: fix a kerneldoc markup

A function has a different name between their prototype
and its kernel-doc markup:
	../include/net/cfg80211.h:1766: warning: expecting prototype for struct cfg80211_sar_chan_ranges. Prototype was for struct cfg80211_sar_freq_ranges instead

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/c7ed4bc4d9e992ead16d3d2df246f3b56dbfb1fb.1610610937.git.mchehab+huawei@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>