arm_mpam: [HACK] Dynamic CLOSID count and RMID index conversions

Compute the CLOSID count and RMID index conversions exported to
resctrl using the new mpam_num_rmids parameter.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>

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Non-bisectable patch -- breaks the MPAM driver.

These changes need to refactored before they can be merged.