icc: qcom: Refactor icc rpmh support

Add bcm voter driver and add support for RPMh specific interconnect
providers so that they may be re-used for icc-next RPMh based provider
drivers.

Change-Id: I6b0db857ed0724dec0386a9961b3a0b8e676efbd
Signed-off-by: David Dai <daidavid1@codeaurora.org>