docs: Fix power model doxygen

Change-Id: I0a9a30bc4a89411e0f1dd897f0d1f05f20790b50
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-on: https://gem5-review.googlesource.com/9981
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
3 files changed