drm/xe: Generate oob before compiling anything

drm/xe: Generate oob before compiling anything

Instead of keep adding more dependencies as WAs are needed in different
places of the driver, just add a rule with all the objects so the code
generation happens before anything else.

While at it, group lines related to wa_oob in the Makefile.

v2: Prefix $(obj) when declaring dependency

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240708213041.1734028-1-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>