i915/pmu: Move execlist stats initialization to execlist specific setup

i915/pmu: Move execlist stats initialization to execlist specific setup

[ Upstream commit c524cd40e8a2a1a36f4898eaf2024beefeb815f3 ]

engine->stats is a union of execlist and guc stat objects. When execlist
specific fields are initialized, the initial state of guc stats is
affected. This results in bad busyness values when using GuC mode. Move
the execlist initialization from common code to execlist specific code.

Fixes: 77cdd054dd2c ("drm/i915/pmu: Connect engine busyness stats from GuC to pmu")
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230912212247.1828681-1-umesh.nerlige.ramappa@intel.com
(cherry picked from commit 4485bd519f5d6d620a29d0547ff3c982bdeeb468)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>