drm/i915/pxp/mtl: Update pxp-firmware packet size

Update the GSC-fw input/output HECI packet size to match
updated internal fw specs.

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Vivaik Balasubrawmanian <vivaik.balasubrawmanian@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230917211933.1407559-3-alan.previn.teres.alexis@intel.com