[patch] atmel: potential underflow in atmel_set_freq()

[Dan Carpenter]

Smatch complains that we cap the upper bound of "fwrq->m" but not the
lower bound.  I don't know if it can actually happen but it's simple
enough to check for negatives.

Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>

diff --git a/drivers/net/wireless/atmel/atmel.c 
b/drivers/net/wireless/atmel/atmel.c
index 8f8f37f..bf2e9a0 100644
--- a/drivers/net/wireless/atmel/atmel.c
+++ b/drivers/net/wireless/atmel/atmel.c
@@ -2275,7 +2275,7 @@ static int atmel_set_freq(struct net_device *dev,
                fwrq->m = ieee80211_frequency_to_channel(f);
        }
        /* Setting by channel number */
-       if ((fwrq->m > 1000) || (fwrq->e > 0))
+       if (fwrq->m < 0 || fwrq->m > 1000 || fwrq->e > 0)
                rc = -EOPNOTSUPP;
        else {
                int channel = fwrq->m;