drm/i915/guc: Fix GuC error capture sizing estimation and reporting

During GuC error capture initialization, we estimate the amount of size
we need for the error-capture-region of the shared GuC-log-buffer.
This calculation was incorrect so fix that. With the fixed calculation
we can reduce the allocation of error-capture region from 4MB to 1MB
(see note2 below for reasoning). Additionally, switch from drm_notice to
drm_debug for the 3X spare size check since that would be impossible to
hit without redesigning gpu_coredump framework to hold multiple captures.

NOTE1: Even for 1x the min size estimation case, actually running out
of space is a corner case because it can only occur if all engine
instances get reset all at once and i915 isn't able extract the capture
data fast enough within G2H handler worker.

NOTE2: With the corrected calculation, a DG2 part required ~77K and a PVC
required ~115K (1X min-est-size that is calculated as one-shot all-engine-
reset scenario).

Fixes: d7c15d76 ("drm/i915/guc: Check sizing of guc_capture output")
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Cc: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris.p.wilson@intel.com>
Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221026060506.1007830-2-alan.previn.teres.alexis@intel.com