habanalabs: support reserving aligned va block

Add support for reserving va block with alignment different than
page size. This is a pre-requisite for allocations needed in future
ASICs

Signed-off-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>