drm/xe/pf: Request 64K aligned allocations for LMTT PD

drm/xe/pf: Request 64K aligned allocations for LMTT PD

The LMTT Page Directory, as well as the directory entries, must be
aligned on a 64KB boundary in VRAM. Use explicit alignment flag to
match hardware requirement.

Bspec: 52404, 67468
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240313104132.1045-3-michal.wajdeczko@intel.com
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>