USB: BUG_ON conversion for wacom.c

this patch converts two if () BUG(); construct to BUG_ON();
which occupies less space, uses unlikely and is safer when
BUG() is disabled.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Acked-by: "Ping Cheng" <pingc@wacom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/input/wacom_sys.c b/drivers/usb/input/wacom_sys.c
index 3c27f9b..31379b8 100644
--- a/drivers/usb/input/wacom_sys.c
+++ b/drivers/usb/input/wacom_sys.c
@@ -223,8 +223,7 @@
 	strlcat(wacom->phys, "/input0", sizeof(wacom->phys));
 
 	wacom_wac->features = get_wacom_feature(id);
-	if (wacom_wac->features->pktlen > 10)
-		BUG();
+	BUG_ON(wacom_wac->features->pktlen > 10);
 
 	input_dev->name = wacom_wac->features->name;
 	wacom->wacom_wac = wacom_wac;