wireless-regdb: allow max bandwidth to be AUTO calculated
wireless-regdb: allow max bandwidth to be AUTO calculated

Allow max bandwidth to be AUTO calculated, base
on contiguous rules. This AUTO ( bw = 0) parameter will be
send to the kernel mode (cfg80211/nl80211) and next maximum
allowed bandwidth will be calculated base on contiguous rules.

Eg.

country PL: DFS-ETSI
	(2402 - 2482 @ 40), (N/A, 20)
	(5170 - 5250 @ AUTO), (N/A, 20)
	(5250 - 5330 @ AUTO), (N/A, 20), DFS
	(5490 - 5710 @ 80), (N/A, 27), DFS

This mean we will calculate maximum bw for rules where
AUTO were set, 160MHz (5330 - 5170) in example above.
So we will get:
	(5170 - 5250 @ 160), (N/A, 20)
	(5250 - 5330 @ 160), (N/A, 20), DFS

In other case:
country FR: DFS-ETSI
	(2402 - 2482 @ 40), (N/A, 20)
	(5170 - 5250 @ AUTO), (N/A, 20)
	(5250 - 5330 @ 80), (N/A, 20), DFS
	(5490 - 5710 @ 80), (N/A, 27), DFS

We will get 80MHz (5250 - 5170):
	(5170 - 5250 @ 80), (N/A, 20)
	(5250 - 5330 @ 80), (N/A, 20), DFS

Signed-off-by: Janusz Dziedzic <a4201e08a607951e17dcd5a575c0fe6bceb34e87@tieto.com>
Signed-off-by: John W. Linville <2a53bac7a5d324865ef46ec4c38b2c0fba1456b4@tuxdriver.com>

perillamint/wireless-regdb-hx,0x90/wireless-regdb,Distrotech/wireless-regdb,vaginessa/wireless-regdb