drm/msm/a6xx: Fix a6xx indexed-regs in devcoreduump

drm/msm/a6xx: Fix a6xx indexed-regs in devcoreduump

[ Upstream commit 06dd5d86c6aef1c7609ca3a5ffa4097e475e2213 ]

Somehow, possibly as a result of rebase gone badly, setting
nr_indexed_regs for pre-a650 a6xx devices lost the setting of
nr_indexed_regs, resulting in values getting snapshot, but omitted
from the devcoredump.

Fixes: e997ae5f45ca ("drm/msm/a6xx: Mostly implement A7xx gpu_state")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/640289/
Signed-off-by: Sasha Levin <sashal@kernel.org>