clk: qcom: clk-rpmh: Add IPA clock support

The clk-rpmh driver only supports on and off RPMh clock resources. Let's
extend the driver by adding support for clocks that are managed by a
different type of RPMh resource known as Bus Clock Manager(BCM). The BCM
is a configurable shared resource aggregator that scales performance
based on a set of frequency points. The Qualcomm IP Accelerator (IPA)
clock is an example of a resource that is managed by the BCM and this a
requirement from the IPA driver in order to scale its core clock.

Signed-off-by: David Dai <daidavid1@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>