zero the stack buffer before giving random garbage to the SCU

some messages take 4 bytes, but only fill 3 bytes....
this patch makes sure that whatever we send to the SCU is zeroed first

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

drivers/platform/x86/intel_scu_ipc.c

@@ -162,6 +162,8 @@ static int pwr_reg_rdwr(u16 *addr, u8 *data, u32 count, u32 op, u32 id)
 
 	mutex_lock(&ipclock);
 
+	memset(cbuf, 0, sizeof(cbuf));
+
 	if (ipcdev.pdev == NULL) {
 		mutex_unlock(&ipclock);
 		return -ENODEV;