habanalabs: add prefetch flag to the MAP operation

This patch let the user decide whether the translations done in the
page tables will be fetched directly to the STLB right after the map.

We want to let the user control whether to perform prefetch upon map
operation.

To do so a memory flag was added, to be used in the MAP ioctl, called
HL_MEM_PREFETCH and if set- the mappings will be fetched directly to
the STLB after map operation.

Signed-off-by: Ohad Sharabi <osharabi@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>