powercap: DTPM: Fix unneeded conversions to micro-Watts

The power values coming from the Energy Model are already in uW.

The PowerCap and DTPM frameworks operate on uW, so all places should
just use the values from the EM.

Fix the code by removing all of the conversion to uW still present in it.

Fixes: ae6ccaa6

 (PM: EM: convert power field to micro-Watts precision and align drivers)
Cc: 5.19+ <stable@vger.kernel.org> # v5.19+
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>