net: pse-pd: tps23881: Simplify function returns by removing redundant checks

Cleaned up several functions in tps23881 by removing redundant checks on
return values at the end of functions. These check has been removed, and
the return statement now directly returns the function result, reducing
the code's complexity and making it more concise.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Kyle Swenson <kyle.swenson@est.tech>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>