media: i2c: tda1997x: Call of_node_put(ep) only once in tda1997x_parse_dt()

An of_node_put(ep) call was immediately used after a return value check
for a v4l2_fwnode_endpoint_parse() call in this function implementation.
Thus call such a function only once instead directly before the check.

This issue was transformed by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>