Staging: oslec bug fix

I have just had a bug fix submitted for Oslec which I have applied to
Oslec SVN. The bug can potentially stops the echo canceller adapting
after a few seconds, although it hasn't caused many problems in
practice.
Signed-off-by: NDavid Rowe <david@rowetel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/echo/echo.c

@@ -395,7 +395,7 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx)
 		old = (int)ec->fir_state.history[ec->fir_state.curr_pos] *
 		    (int)ec->fir_state.history[ec->fir_state.curr_pos];
 		ec->Pstates +=
-		    ((new - old) + (1 << ec->log2taps)) >> ec->log2taps;
+		    ((new - old) + (1 << (ec->log2taps-1))) >> ec->log2taps;
 		if (ec->Pstates < 0)
 			ec->Pstates = 0;
 	}