drm/i915/error: fix i915_capture_error_state() kernel-doc

drivers/gpu/drm/i915/i915_gpu_error.c:2174: warning: Function parameter or member 'dump_flags' not described in 'i915_capture_error_state'

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20524292b002800975d82d23b5bd47da878f1733.1683041799.git.jani.nikula@intel.com