Revert "Board-shooter: experiment, increase SMI allocation size"

This reverts commit e8b132e2d69252fcffbece076740e7ae82346add.
Board-shooter & board-shooter_u: add back the ADSP2 heap

3D camera functionality depends on the ADSP2 heap.

Signed-off-by: Sultanxda <sultanxda@gmail.com>