Input: bcm5974 - set BUTTONPAD property

Some bcm5974 trackpads have a physical button beneath the physical surface.
This patch sets the property bit so user space applications can detect the
trackpad type and act accordingly.

Signed-off-by: Jussi Pakkanen <jussi.pakkanen@canonical.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/mouse/bcm5974.c b/drivers/input/mouse/bcm5974.c
index 5ec617e..913e9fa4 100644
--- a/drivers/input/mouse/bcm5974.c
+++ b/drivers/input/mouse/bcm5974.c
@@ -433,6 +433,9 @@
 	__set_bit(BTN_TOOL_QUADTAP, input_dev->keybit);
 	__set_bit(BTN_LEFT, input_dev->keybit);
 
+	if (cfg->caps & HAS_INTEGRATED_BUTTON)
+		__set_bit(INPUT_PROP_BUTTONPAD, input_dev->propbit);
+
 	input_set_events_per_packet(input_dev, 60);
 }