pinctrl: ti: fix error return code of ti_iodelay_probe()

pinctrl: ti: fix error return code of ti_iodelay_probe()

When ti_iodelay_pinconf_init_dev() fails, no error return code of
ti_iodelay_probe() is assigned.
To fix this bug, ret is assigned with the return value of
ti_iodelay_pinconf_init_dev(), and then ret is checked.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Link: https://lore.kernel.org/r/20210306125122.15043-1-baijiaju1990@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>