atm: eni: fix uninitialized variable warning

BugLink: https://bugs.launchpad.net/bugs/1864774

[ Upstream commit 30780d08 ]

With -O3, gcc has found an actual unintialized variable stored
into an mmio register in two instances:

drivers/atm/eni.c: In function 'discard':
drivers/atm/eni.c:465:13: error: 'dma[1]' is used uninitialized in this function [-Werror=uninitialized]
   writel(dma[i*2+1],eni_dev->rx_dma+dma_wr*8+4);
             ^
drivers/atm/eni.c:465:13: error: 'dma[3]' is used uninitialized in this function [-Werror=uninitialized]

Change the code to always write zeroes instead.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/atm/eni.c

@@ -372,7 +372,7 @@ static int do_rx_dma(struct atm_vcc *vcc,struct sk_buff *skb,
 		here = (eni_vcc->descr+skip) & (eni_vcc->words-1);
 		dma[j++] = (here << MID_DMA_COUNT_SHIFT) | (vcc->vci
 		    << MID_DMA_VCI_SHIFT) | MID_DT_JK;
-		j++;
+		dma[j++] = 0;
 	}
 	here = (eni_vcc->descr+size+skip) & (eni_vcc->words-1);
 	if (!eff) size += skip;
@@ -445,7 +445,7 @@ static int do_rx_dma(struct atm_vcc *vcc,struct sk_buff *skb,
 	if (size != eff) {
 		dma[j++] = (here << MID_DMA_COUNT_SHIFT) |
 		    (vcc->vci << MID_DMA_VCI_SHIFT) | MID_DT_JK;
-		j++;
+		dma[j++] = 0;
 	}
 	if (!j || j > 2*RX_DMA_BUF) {
 		printk(KERN_CRIT DEV_LABEL "!j or j too big!!!\n");