habanalabs/gaudi: scrub HBM to a specific value

In order to enhance debuggability, we will scrub the whole HBM to
a specific value, in case HBM scrubbing is enabled. Scrubbing will be
performed after reset and after user closes the FD.

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