soc: bcm: Move power-domain drivers to the genpd dir

soc: bcm: Move power-domain drivers to the genpd dir

To simplify with maintenance let's move the bcm power-domain drivers to the
new genpd directory. Going forward, patches are intended to be managed
through a separate git tree, according to MAINTAINERS.

While moving the drivers, we end up with a directory for bcm63xx that only
contains a Kconfig file, which seems a bit silly. Let's therefore also move
the Kconfig options into the Kconfig file a directory above, as it allows
us to drop the directory too.

Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: <linux-mips@vger.kernel.org>
Cc: <linux-rpi-kernel@lists.infradead.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>