Add some more debugging printf()s to complain if the ath_buf tx queue
doesn't match the actual hardware queue this frame is queued to.

I'm trying to ensure that the holding buffers are actually being queued
to the same TX queue as the holding buffer that they end up on.
I'm pretty sure this is all correct so if this complains, it'll be due
to some kind of subtle broken-ness that needs fixing.

This is only done for legacy hardware, not EDMA hardware.

Tested:

* AR5416 STA mode, very lightly