V4L/DVB (9607): em28xx: Properly implement poll support for IR's

The first em28xx were based on i2c IR's. However, some newer designs
are coming with a polling-based IR. Those are done by reading a register
set at em28xx.

This patch adds core polling support for those devices. Later patches will
add support for some device-specific IR's.

This patch adds the same basic IR polling code used by bttv, cx88 and saa7134, and
shares the common getkey masks defined at ir-common.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c
index e425111..1d38bfa 100644
--- a/drivers/media/video/em28xx/em28xx-cards.c
+++ b/drivers/media/video/em28xx/em28xx-cards.c
@@ -1843,4 +1843,6 @@
 #endif
 
 	em28xx_config_tuner(dev);
+
+	em28xx_ir_init(dev);
 }