iw: Add support for specifying the 160MHz bandwidth when setting the channel/frequency

iw: Add support for specifying the 160MHz bandwidth when setting the channel/frequency

The current iw tool only supports the direct setting of
[NOHT|HT20|HT40+|HT40-|5MHz|10MHz|80MHz] bandwidth
when setting the channel/frequency.

If we want to set the 160MHz bandwidth,
we need to calculate the center frequency ourselves,
which is inconvenient.

E.g:
iw phy phy0 set freq 5220 160 5250

From now on we can:
iw phy phy0 set channel 44 160MHz
iw phy phy0 set freq 5220 160MHz

This is much more convenient.

Signed-off-by: AK Deng <ttttabcd@protonmail.com>
Link: https://lore.kernel.org/r/cIf-30s-5axo5iDqyzwY9VTVB_JLKCXbxlXdODMSK61q-yFzR6rtAk8URRAPavRlllrwXr1Q-jtem_upoCNKd_fba8qmM0DpJn0O7MIkq6o=@protonmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>