reset: rzg2l-usbphy-ctrl: Propagate the return value of regmap_field_update_bits()

reset: rzg2l-usbphy-ctrl: Propagate the return value of regmap_field_update_bits()

Propagate the return value of regmap_field_update_bits() to avoid losing
any possible error. With this, the return type of
rzg2l_usbphy_ctrl_set_pwrrdy() was updated accordingly.

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>