cfg80211: extend ieee80211_operating_class_to_band() for 6GHz

Add 6GHz operating class range as defined in 802.11ax D4.1 Annex E.

Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Leon Zegers <leon.zegers@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Link: https://lore.kernel.org/r/1564745465-21234-5-git-send-email-arend.vanspriel@broadcom.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Git-commit: 852f04620e5b7c27eadbf81d086d04f61431c9dc
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next.git


Change-Id: Ie2a375417c88eaad69909e6ab9875a6f69747293
CRs-Fixed: 2536745
Signed-off-by: Liangwei Dong <liangwei@codeaurora.org>