video: fbdev: remove dead igafb driver

igafb driver hasn't compiled since at least kernel v2.6.34 as
commit 6016a363 ("of: unify phandle name in struct device_node")
missed updating igafb.c to use dp->phandle instead of dp->node.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>