staging: gdm72xx: Remove useless cast on void pointer

void pointers do not need to be cast to other pointer types.

The semantic patch used to find this:

@r@
expression x;
void* e;
type T;
identifier f;
@@

(
  *((T *)e)
|
  ((T *)x)[...]
|
  ((T *)x)->f
|
- (T *)
  e
)

Build tested it.
Signed-off-by: Tapasweni Pathak <tapaswenipathak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gdm72xx/gdm_wimax.c

@@ -115,7 +115,7 @@ static void gdm_wimax_event_rcv(struct net_device *dev, u16 type, void *msg,
 {
 	struct nic *nic = netdev_priv(dev);
 
-	u8 *buf = (u8 *)msg;
+	u8 *buf = msg;
 	u16 hci_cmd =  (buf[0]<<8) | buf[1];
 	u16 hci_len = (buf[2]<<8) | buf[3];