rsi: Fix memory leak in module unload

Observed crash when module is unloaded if CONFIG_RSI_DEBUGSFS is not set.
	Fix: Debugfs entry removal moved inside CONFIG_RSI_DEBUGSFS flag in
             function rsi_mac80211_detach()
Memory leak found and fixed for below structures in function rsi_mac80211_detach()
	* channel list for each supported band
	* rsi debugfs info

Signed-off-by: Prameela Rani Garnepudi <prameela.j04cs@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>