The incorrect size was causing "CP | AHB bus error" when snapshotting
the GPU state on a6xx gen4 (a660 family).

Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/26Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Fixes: 1707add8 ("drm/msm/a6xx: Add a6xx gpu state")
Patchwork: https://patchwork.freedesktop.org/patch/546763/