soc: qcom: ocmem: Fix missing put_device() call in of_get_ocmem

The reference taken by 'of_find_device_by_node()' must be released when
not needed anymore.
Add the corresponding 'put_device()' in the error handling path.

Fixes: 01f937ff ("soc: qcom: ocmem: don't return NULL in of_get_ocmem")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220107073126.2335-1-linmq006@gmail.com