mfd: anatop-mfd: remove anatop driver

The anatop registers are accessed via syscon now, no one will use
mfd anatop driver anymore, remove it.

Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>