When a CPU comes online, it may bring a newly accessible MSC with it. Only
the default partid has its value reset by hardware, and even then the MSC might
not have been reset since its config was previously dirtied. e.g. Kexec.

Any in-use partid must have its configuration restored, or reset.
In-use partids may be held in caches and evicted later.

MSC are also reset when CPUs are taken offline to cover cases where firmware
doesn't reset the MSC over reboot using UEFI, or kexec where there is no
firmware involvement.

If the configuration for a RIS has not been touched since it was brought online,
it does not need resetting again.

To reset, write the maximum values for all discovered controls.

CC: Rohit Mathew <redacted>
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>

Reviewed-by: Shaopeng Tan <redacted>