drm/i915/mtl: Resize noa_wait BO size to save restore GPR regs

On MTL, gt->scratch was using stolen lmem. An MI_SRM to stolen lmem
caused a hang that was attributed to saving and restoring the GPR
registers used for noa_wait.

Add an additional page in noa_wait BO to save/restore GPR registers for
the noa_wait logic.

Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221212220902.1819159-2-umesh.nerlige.ramappa@intel.com