iw: print out eirp for triplets on scan

iw: print out eirp for triplets on scan

When debugging country IE parsing when scanning you will not see this:

	Channels [1 - 1] @ 14 dBm
	Channels [2 - 10] @ 21 dBm
	Channels [11 - 11] @ 14 dBm

Instead of this:

	Channels [1 - 1]
	Channels [2 - 10]
	Channels [11 - 11

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>