reset: fix optional reset_control_get stubs to return NULL

reset: fix optional reset_control_get stubs to return NULL

commit 0ca10b60ceeb5372da01798ca68c116ae45a6eb6 upstream.

When RESET_CONTROLLER is not enabled, the optional reset_control_get
stubs should now also return NULL.

Since it is now valid for reset_control_assert/deassert/reset/status/put
to be called unconditionally, with NULL as an argument for optional
resets, the stubs are not allowed to warn anymore.

Fixes: bb475230b8e5 ("reset: make optional functions really optional")
Reported-by: Andrzej Hajda <a.hajda@samsung.com>
Tested-by: Andrzej Hajda <a.hajda@samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Cc: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>