staging: vt6656: sparse fixes: iwctl_siwgenie use memcpy.

extra is in kernel space replace copy_from_user with
memcpy with no need to error check.

We already know that extra is valid by error checking
on wrq->length.

sparse warning
iwctl.c:1567:53: warning: incorrect type in argument 2 (different address spaces)
iwctl.c:1567:53: expected void const [noderef] <asn:1>*from
iwctl.c:1567:53: got char *extra

Signed-off-by: Malcolm Priestley <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/vt6656/iwctl.c

···
 			goto out;
 		}
 		memset(pMgmt->abyWPAIE, 0, MAX_WPA_IE_LEN);
-		if (copy_from_user(pMgmt->abyWPAIE, extra, wrq->length)) {
-			ret = -EFAULT;
-			goto out;
-		}
+
+		memcpy(pMgmt->abyWPAIE, extra, wrq->length);
 		pMgmt->wWPAIELen = wrq->length;
 	} else {
 		memset(pMgmt->abyWPAIE, 0, MAX_WPA_IE_LEN);