habanalabs: align armcp_packet structure to 8 bytes

Once there is a 64-bit field in a structure, GCC compiler for ARM aligns
the structure to 8 bytes. In order to avoid confusion when these
structures are being passed between CPUs from different architectures, we
explicitly align the structure to 8 bytes.

Reviewed-by: Omer Shpigelman <oshpigelman@habana.ai>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>