drm/xe: Fix print of RING_EXECLIST_SQ_CONTENTS_HI

On xe_hw_engine_print_state we were printing:
value_of(0x510) + 4 instead of
value_of(0x514) as desired.

So, let's properly define a RING_EXECLIST_SQ_CONTENTS_HI
register to fix the issue and also to avoid other issues
like that.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>