remoteproc: st: Call of_node_put() on iteration error

remoteproc: st: Call of_node_put() on iteration error

Function of_phandle_iterator_next() calls of_node_put() on the last
device_node it iterated over, but when the loop exits prematurely it has
to be called explicitly.

Fixes: 3df52ed7f269 ("remoteproc: st: add reserved memory support")
Cc: stable@vger.kernel.org
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20230320221826.2728078-3-mathieu.poirier@linaro.org
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>