pinctrl: canaan: k230: Fix NULL pointer dereference when parsing devicetree

pinctrl: canaan: k230: Fix NULL pointer dereference when parsing devicetree

When probing the k230 pinctrl driver, the kernel triggers a NULL pointer
dereference. The crash trace showed:
[    0.732084] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000068
[    0.740737] ...
[    0.776296] epc : k230_pinctrl_probe+0x1be/0x4fc

In k230_pinctrl_parse_functions(), we attempt to retrieve the device
pointer via info->pctl_dev->dev, but info->pctl_dev is only initialized
after k230_pinctrl_parse_dt() completes.

At the time of DT parsing, info->pctl_dev is still NULL, leading to
the invalid dereference of info->pctl_dev->dev.

Use the already available device pointer from platform_device
instead of accessing through uninitialized pctl_dev.

Fixes: d94a32ac688f ("pinctrl: canaan: k230: Fix order of DT parse and pinctrl register")
Signed-off-by: Jiayu Du <jiayu.riscv@isrc.iscas.ac.cn>
Signed-off-by: Linus Walleij <linusw@kernel.org>