drm/xe: Correct BMG VSEC header sizing

drm/xe: Correct BMG VSEC header sizing

The intel_vsec_header information for the crashlog feature is
incorrect.

Update the VSEC header with correct sizing and count.

Since the crashlog entries are "merged" (num_entries = 2), the
separate capabilities entries must be merged as well.

Fixes: 0c45e76fcc62 ("drm/xe/vsec: Support BMG devices")
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Reviewed-by: David E. Box <david.e.box@linux.intel.com>
Link: https://lore.kernel.org/r/20250713172943.7335-4-michael.j.ruhl@intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>