video: amba-clcd: Make CLCD driver available on more platforms

The CLCD driver is used on ARM reference models for ARMv8 so add ARM64
to the list of dependencies. The driver also has no build time dependencies
on ARM (stubs are provided for ARM-specific DMA functions in the code) so
make it available with COMPILE_TEST in order to maximise build coverage.

Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>