PM: EM: Fix yamllint warnings in the EM YNL spec

PM: EM: Fix yamllint warnings in the EM YNL spec

The energy model YNL spec has the following two warnings
when checking with yamlint:

 3:1    warning missing document start "---"  (document-start)
 107:13 error   wrong indentation: expected 10 but found 12  (indentation)

So let’s fix whose lint warnings.

Fixes: bd26631ccdfd ("PM: EM: Add em.yaml and autogen files")
Suggested-by: Donald Hunter <donald.hunter@gmail.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Changwoo Min <changwoo@igalia.com>
Link: https://patch.msgid.link/20260108053212.642478-2-changwoo@igalia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>