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: David Howells <dhowells@redhat.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/sound/drivers/vx/vx_hwdep.c b/sound/drivers/vx/vx_hwdep.c
index 1dfe694..efd22e9 100644
--- a/sound/drivers/vx/vx_hwdep.c
+++ b/sound/drivers/vx/vx_hwdep.c
@@ -183,7 +183,7 @@
 		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;
 	}