regulator: qcom_spmi: Fix warning Bad of_node_put()

regulator: qcom_spmi: Fix warning Bad of_node_put()

For of_find_node_by_name(), you typically pass what the previous call
returned. Therefore, of_find_node_by_name() increases the refcount of
the returned node, and decreases the refcount of the node passed as the
first argument.

of_find_node_by_name() is incorrectly used, and produces a warning.
Fix the warning by using the more suitable function
of_get_child_by_name().

Also add a missing of_node_put() for the returned value, since this was
previously being leaked.

OF: ERROR: Bad of_node_put() on /soc/qcom,spmi@400f000/pmic@3/regulators
CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W         4.18.0-rc4-00223-gefd7b360b70e #12
Hardware name: Qualcomm Technologies, Inc. DB820c (DT)
Call trace:
 dump_backtrace+0x0/0x1a8
 show_stack+0x14/0x20
 dump_stack+0x90/0xb4
 of_node_release+0x74/0x78
 kobject_put+0x90/0x1f0
 of_node_put+0x14/0x20
 of_find_node_by_name+0x80/0xd8
 qcom_spmi_regulator_probe+0x30c/0x508

Fixes: 0caecaa87202 ("regulator: qcom_spmi: Add support for SAW")
Signed-off-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>