arm_mpam: resctrl: Implement resctrl_arch_rmid_read()

Now that we can configure and read monitors, implement
resctrl_arch_rmid_read(). We assume that by the time we've scheduled
around to configure the monitor, it will be ready to read. If not,
we retry with a 1 second timeout.

Because resctrl_arch_rmid_read() is domain local, we want to use
resctrl_get_domain_from_cpu(). Update Kconfig so that we now
link against resctrl too.

Signed-off-by: James Morse <james.morse@arm.com>