ARM: amba: Make driver_override output consistent with other buses

BugLink: http://bugs.launchpad.net/bugs/1768825

commit 5f536246 upstream.

For AMBA devices with unconfigured driver override, the
"driver_override" sysfs virtual file is empty, while it contains
"(null)" for platform and PCI devices.

Make AMBA consistent with other buses by dropping the test for a NULL
pointer.

Note that contrary to popular belief, sprintf() handles NULL pointers
fine; they are printed as "(null)".
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/amba/bus.c

@@ -69,9 +69,6 @@ static ssize_t driver_override_show(struct device *_dev,
 {
 	struct amba_device *dev = to_amba_device(_dev);
 
-	if (!dev->driver_override)
-		return 0;
-
 	return sprintf(buf, "%s\n", dev->driver_override);
 }