atmel: Replace mdelay() with msleep() in probe_atmel_card()

probe_atmel_card() is never called in atomic context.
It calls mdelay() to busily wait, which is not necessary.
mdelay() can be replaced with msleep().

This is found by a static analysis tool named DCNS written by myself.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/atmel/atmel.c

@@ -3677,7 +3677,7 @@ static int probe_atmel_card(struct net_device *dev)
 		atmel_write16(dev, GCR, 0x0060);
 
 	atmel_write16(dev, GCR, 0x0040);
-	mdelay(500);
+	msleep(500);
 
 	if (atmel_read16(dev, MR2) == 0) {
 		/* No stored firmware so load a small stub which just