arm: mach-imx: use CONFIG_$(SPL_)SATA instead of CONFIG_SATA

This avoid an error with enable_sata_clock when
defined(CONFIG_SATA) is changed to CONFIG_IS_ENABLED(SATA).

Signed-off-by: Troy Kisky <troykiskyboundary@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>