[bwn] check DUALPHY; add BCM4322 to the don't-override list.

• DUALPHY in TGSHIGH tells us there's a phy that is dualband, rather than two separate PHYs/MACs (which we almost but don't quite yet support.) Use it.

• Add the BCM4322 PCI ID to the list of devices we don't override. This means the 2g/5g flags are preserved, and thus we get 5GHz operation (with N-PHY, of course.)

Tested:

• BCM4311, STA mode (11bg)
• BCM4312, STA mode (11bg)
• BCM4321, STA mode (11abg)

Sponsored by: Palm Springs