drm/xe/fbdev: Limit the usage of stolen for LNL+

drm/xe/fbdev: Limit the usage of stolen for LNL+

As per recommendation in the workarounds:
WA_22019338487

There is an issue with accessing Stolen memory pages due a
hardware limitation. Limit the usage of stolen memory for
fbdev for LNL+. Don't use BIOS FB from stolen on LNL+ and
assign the same from system memory.

v2: Corrected the WA Number, limited WA to LNL and
    Adopted XE_WA framework as suggested by Lucas and Matt.

v3: Introduced the waxxx_display to implement display side
    of WA changes on Lunarlake. Used xe_root_mmio_gt and
    avoid the for loop (Suggested by Lucas)

v4: Fixed some nits (Luca)

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240717082252.3875909-1-uma.shankar@intel.com