habanalabs: context cleanup cosmetics

No need to check the return value if the following action is the same for
both cases. In addition, now that hl_ctx_free() doesn't print if the
context is not released, its name can be misleading as the context might
stay alive after it is executed with no indication for that.
Hence we can discard it and simply put the refcount.

Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>