net: nb8800: avoid uninitialized variable warning

The nb8800_poll() function initializes the 'next' variable in the
loop looking for new input data. We know this will be called at
least once because 'budget' is a guaranteed to be a positive number
when we enter the function, but the compiler doesn't know that
and warns when the variable is used later:

drivers/net/ethernet/aurora/nb8800.c: In function 'nb8800_poll':
drivers/net/ethernet/aurora/nb8800.c:350:21: warning: 'next' may be used uninitialized in this function [-Wmaybe-uninitialized]

Changing the 'while() {}' loop to 'do {} while()' makes it obvious
to the compiler what is going on so it no longer warns.

Signed-off-by: Arnd Bergmann <[e-mail]>
Acked-by: Mans Rullgard <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/aurora/nb8800.c

···
 	nb8800_tx_done(dev);
 
 again:
-	while (work < budget) {
+	do {
 		struct nb8800_rx_buf *rxb;
 		unsigned int len;
 
···
 		rxd->report = 0;
 		last = next;
 		work++;
-	}
+	} while (work < budget);
 
 	if (work) {
 		priv->rx_descs[last].desc.config |= DESC_EOC;