Restart TX rate control algorithm for a peer node, if its current TX

Restart TX rate control algorithm for a peer node, if its current TX
rate index is beyond the number of TX rates it supports.

This could happen at least in following way:
1) Start a 11g HOSTAP, which uses TX rate control algorithm
2) Use a 11g cardbus wireless card as STA, set its mode to "auto" or
   "11g" and join the BSS created by HOSTAP
3) Transmit some packets from HOSTAP to STA and make sure that TX rate
   index for the STA reaches maximum.
4) Unplug the cardbus wireless card, so it has no chance to send out
   disassociation management frame.
5) Plug the cardbus wireless card back immediately, set its mode to
   "11b" and join the BSS created by HOSTAP again.