memory: tegra: Make CPU cluster BW request a multiple of MC channels

Make CPU cluster's bandwidth (BW) request a multiple of MC channels.
CPU OPP tables have BW info per MC channel. But, the actual BW depends
on the number of MC channels which can change as per the boot config.
Get the number of MC channels which are actually enabled in current
boot configuration and multiply the BW request from a CPU cluster with
the number of enabled MC channels. This is not required to be done for
other MC clients.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>