cpufreq: docs: Reflect latency changes in docs

cpufreq: docs: Reflect latency changes in docs

There were two changes related to transition latency recently.
Namely commit e13aa799c2a6 ("cpufreq: Change default transition delay
to 2ms") and
commit 37c6dccd6837 ("cpufreq: Remove LATENCY_MULTIPLIER").

Both changed the defaults / maximums so let the documentation
reflect that.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/46853b6e-bad5-4ace-9b23-ff157f234ae3@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>