ata: fix Calxeda Highbank SATA driver dependencies

Make sata_highbank host driver depend on ARCH_HIGHBANK config option
as Calxeda Highbank SATA support is specific to Calxeda Highbank
SoCs and the driver to work requires suitable device tree node to
be defined.  Additionally allow the driver build if COMPILE_TEST
config option is set.

Cc: Mark Langsdorf <mark.langsdorf@calxeda.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>