drm/xe/guc: Allocate GuC data structures in system memory for initial load

GuC load will need to happen at an earlier point in probe, where local
memory is not yet available. Use system memory for GuC data structures
used for initial "hwconfig" load, and realloc at a later,
"post-hwconfig" load if needed, when local memory is available.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240219130530.1406044-1-michal.winiarski@intel.com