linux-wandboard

ARM: imx: let IMX_HAVE_PLATFORM_IMX_FB select HAVE_FB_IMX

This way FB_IMX can just depend on HAVE_FB_IMX and machines
just need to select IMX_HAVE_PLATFORM_IMX_FB without bothering
about HAVE_FB_IMX.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>