ARM: bcm: clean-up unneeded kconfig selects

Multi-platform support implies all these options are already selected and
individual platforms don't need to select them.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Christian Daudt <bcm@fixthebug.org>
Cc: Matt Porter <mporter@linaro.org>
Cc: bcm-kernel-feedback-list@broadcom.com