accel/habanalabs: fix DRAM BAR base address calculation

When the DRAM region size in the BAR is not a power of 2, calculating
the corresponding BAR base address should be done using the offset from
the DRAM start address, and not using directly the DRAM address.

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>