habanalabs: re-factor memory module code

Some of the functions in the memory module code were too long and/or
contained multiple operations that are not always done together. Re-factor
the code by dividing those functions to smaller functions which are more
readable and maintainable.

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