regulator: tps65086: Fix DT node referencing in of_parse_cb

When we check for additional DT properties in the current node we
use the device_node passed in with the configuration data, this
will not point to the correct DT node, use the one passed in
for this purpose.

Fixes: d2a2e729 ("regulator: tps65086: Add regulator driver for the TPS65086 PMIC")
Reported-by: Steven Kipisz <s-kipisz2@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Tested-by: Steven Kipisz <s-kipisz2@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>