net: designware: Fix alignment of buffer descriptors

It's important that buffer descriptors are aligned in accordance to GMAC
data bus width (32/64/128-bit). It's safe to align to 128-bit (16-bytes)
for every bus width type.

If buffer descriptor is improperly aligned GMAC discards lower bits of
provided address and as a result reads from improper location that
doesn't match expected fields.

Commit ef76025a99 "net: Multiple
updates/enhancements to designware.c" introduced another structure
member "link_printed" right before buffer descriptors while "padding"
member was left untouched. This together with alignment of structure
itself to 16-byte boundary forces buffer descriptoprs always to be
4-byte aligned that causes driver complete disfunction if GMAC bus width
is 64 or 128-bit.

Proposed change makes sure all buffer descriptors are 16-byte (128-bit)
aligned.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Patch: 277902

drivers/net/designware.h

@@ -112,7 +112,7 @@ struct dmamacdescr {
 	u32 dmamac_cntl;
 	void *dmamac_addr;
 	struct dmamacdescr *dmamac_next;
-};
+} __aligned(16);
 
 /*
  * txrx_status definitions
@@ -224,8 +224,7 @@ struct dw_eth_dev {
 	u32 tx_currdescnum;
 	u32 rx_currdescnum;
 	u32 phy_configured;
-	int link_printed;
-	u32 padding;
+	u32 link_printed;
 
 	struct dmamacdescr tx_mac_descrtable[CONFIG_TX_DESCR_NUM];
 	struct dmamacdescr rx_mac_descrtable[CONFIG_RX_DESCR_NUM];
@@ -237,7 +236,7 @@ struct dw_eth_dev {
 	struct eth_dma_regs *dma_regs_p;
 
 	struct eth_device *dev;
-} __attribute__ ((aligned(8)));
+};
 
 /* Speed specific definitions */
 #define SPEED_10M		1