mt76: round up length on mt76_wr_copy

When beacon length is not a multiple of 4, the beacon could be sent with
the last 1-3 bytes corrupted. The skb data is guaranteed to have enough
room for reading beyond the end, because it is always followed by
skb_shared_info, so rounding up is safe.
All other callers of mt76_wr_copy have multiple-of-4 length already.

Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mmio.c

@@ -43,7 +43,7 @@ static u32 mt76_mmio_rmw(struct mt76_dev *dev, u32 offset, u32 mask, u32 val)
 static void mt76_mmio_copy(struct mt76_dev *dev, u32 offset, const void *data,
 			   int len)
 {
-	__iowrite32_copy(dev->mmio.regs + offset, data, len >> 2);
+	__iowrite32_copy(dev->mmio.regs + offset, data, DIV_ROUND_UP(len, 4));
 }
 
 static int mt76_mmio_wr_rp(struct mt76_dev *dev, u32 base,

drivers/net/wireless/mediatek/mt76/usb.c

@@ -164,7 +164,7 @@ static void mt76u_copy(struct mt76_dev *dev, u32 offset,
 	int i, ret;
 
 	mutex_lock(&usb->usb_ctrl_mtx);
-	for (i = 0; i < (len / 4); i++) {
+	for (i = 0; i < DIV_ROUND_UP(len, 4); i++) {
 		put_unaligned_le32(val[i], usb->data);
 		ret = __mt76u_vendor_request(dev, MT_VEND_MULTI_WRITE,
 					     USB_DIR_OUT | USB_TYPE_VENDOR,