regulator: plug of_node leak in regulator_register()'s error path

By calling device_initialize() earlier and noting that kfree(NULL) is
ok, we can save a bit of code in error handling and plug of_node leak.
Fixed commit already did part of the work.

Fixes: 9177514c

 ("regulator: fix memory leak on error path of regulator_register()")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/f5035b1b4d40745e66bacd571bbbb5e4644d21a1.1597195321.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown <broonie@kernel.org>