OMAP: OMAPFB: disable old omapfb for OMAP4 builds

Build fails when OMAP4 and FB_OMAP are defined:

drivers/built-in.o: In function `omapfb_do_probe':
drivers/video/omap/omapfb_main.c:1773: undefined reference to `omap2_int_ctrl'

Old omapfb does not work on OMAP4, and never will. Change the omapfb
build dependency so that old omapfb depends on OMAP1/2/3, fixing the
build for plain OMAP4 builds.
Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>

drivers/video/omap/Kconfig

 config FB_OMAP
 	tristate "OMAP frame buffer support (EXPERIMENTAL)"
-	depends on FB && ARCH_OMAP && (OMAP2_DSS = "n")
-
+	depends on FB && (OMAP2_DSS = "n")
+	depends on ARCH_OMAP1 || ARCH_OMAP2 || ARCH_OMAP3
 	select FB_CFB_FILLRECT
 	select FB_CFB_COPYAREA
 	select FB_CFB_IMAGEBLIT