mediatek: fix a sleep while atomic bug inside the ethernet driver

this sometimes happens when we have hw nat enabled.

Signed-off-by: John Crispin <john@phrozen.org>

target/linux/mediatek/patches-4.9/0063-atomic-sleep.patch

@@ -0,0 +1,40 @@
+Index: linux-4.9.50/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+===================================================================
+--- linux-4.9.50.orig/drivers/net/ethernet/mediatek/mtk_eth_soc.c
++++ linux-4.9.50/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+@@ -1533,7 +1533,10 @@ static void mtk_hwlro_rx_uninit(struct m
+ 	for (i = 0; i < 10; i++) {
+ 		val = mtk_r32(eth, MTK_PDMA_LRO_CTRL_DW0);
+ 		if (val & MTK_LRO_RING_RELINQUISH_DONE) {
+-			msleep(20);
++			if (in_atomic())
++				mdelay(20);
++			else
++				msleep(20);
+ 			continue;
+ 		}
+ 		break;
+@@ -1951,7 +1954,10 @@ static void mtk_stop_dma(struct mtk_eth
+ 	for (i = 0; i < 10; i++) {
+ 		val = mtk_r32(eth, glo_cfg);
+ 		if (val & (MTK_TX_DMA_BUSY | MTK_RX_DMA_BUSY)) {
+-			msleep(20);
++			if (in_atomic())
++				mdelay(20);
++			else
++				msleep(20);
+ 			continue;
+ 		}
+ 		break;
+@@ -1996,7 +2002,10 @@ static void ethsys_reset(struct mtk_eth
+ 			   reset_bits,
+ 			   reset_bits);
+ 
+-	usleep_range(1000, 1100);
++	if (in_atomic())
++		udelay(1000);
++	else
++		usleep_range(1000, 1100);
+ 	regmap_update_bits(eth->ethsys, ETHSYS_RSTCTRL,
+ 			   reset_bits,
+ 			   ~reset_bits);