ARM: imx: apalis_imx6: Drop ad-hoc SATA binding

Drop the ad-hoc AHCI binding code, this is superseded by
CONFIG_DWC_AHSATA_AHCI=y resp. drivers/ata/dwc_ahsata.c

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Cc: Max Krummenacher <max.krummenacher@toradex.com>
Cc: Stefan Agner <stefan.agner@toradex.com>
Cc: Stefano Babic <sbabic@denx.de>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>