habanalabs: remove DMA mask hack for Goya

This patch removes the non-standard DMA mask setting for Goya. Now that
the device CPU goes through the MMU, we are not limited to allocating the
CPU accessible memory area in the address space of under 39 bits.
Therefore, we don't need to set the DMA masking twice during
initialization, a practice that is not working on POWER architecture.

The patch sets the DMA mask to 48 bits once during the initialization. The
address of the CPU accessible memory area is configured to the MMU and the
matching VA is given to the device CPU.

Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>