habanalabs: add MMU prefetch to ASIC-specific code

This is necessary pre-requisite for future ASIC support, where MMU
TLB prefetch is supported.

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>