accel/habanalabs: restructure function that checks heartbeat received

accel/habanalabs: restructure function that checks heartbeat received

The function returned an error code which isn't propagated up the stack
(nor is it printed).

The return value is only checked for =0 or !=0 which implies bool return
value.

The function signature is updated accordingly, renamed, and slightly
refactored.

Signed-off-by: Ohad Sharabi <osharabi@habana.ai>
Reviewed-by: Ofir Bitton <obitton@habana.ai>
Signed-off-by: Ofir Bitton <obitton@habana.ai>