dz: test after postfix decrement fails in dz_console_putchar()

When loops reaches 0 the postfix decrement still subtracts, so the subsequent
test fails.

Signed-off-by: Roel Kluin <[e-mail]>
Acked-by: Maciej W. Rozycki <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/serial/dz.c

···
 		dz_out(dport, DZ_TCR, mask);
 		iob();
 		udelay(2);
-	} while (loops--);
+	} while (--loops);
 
 	if (loops)				/* Cannot send otherwise. */
 		dz_out(dport, DZ_TDR, ch);