Fix a const pointer usage warning in the Digigram VX soundcard driver

Fix a const pointer usage warning in the Digigram VX soundcard driver.  A
const pointer is being passed to copy_from_user() to load the firmware into.
This is okay in this case because the function has allocated the firmware
struct itself, but the const qualifier will be part of the firmware 
struct - so the patch casts the const away.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

sound/drivers/vx/vx_hwdep.c

@@ -183,7 +183,7 @@ static int vx_hwdep_dsp_load(struct snd_hwdep *hw,
 		kfree(fw);
 		return -ENOMEM;
 	}
-	if (copy_from_user(fw->data, dsp->image, dsp->length)) {
+	if (copy_from_user((void *)fw->data, dsp->image, dsp->length)) {
 		free_fw(fw);
 		return -EFAULT;
 	}