accel/habanalabs: fix a maybe-uninitialized compilation warnings

Initialize 'index' in gaudi2_handle_qman_err() and 'offset' in
gaudi2_get_nic_idle_status() to avoid "maybe-uninitialized" compilation
warnings.

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