pinctrl: devicetree: don't free uninitialized dev_name on error path

In the Linux kernel, the following vulnerability has been resolved: pinctrl: devicetree: don't free uninitialized dev_name on error path dt_remember_or_free_map() duplicates dev_name for each map entry. If kstrdup_const() fails, dt_free_map() frees dev_name in all num_maps entries, including entries that have not been initialized. Some pinctrl drivers, including pinctrl-imx, allocate the map with kmalloc() and leave dev_name for the core to initialize. The untouched entries therefore contain uninitialized data which is passed to kfree_const(). Reproduced on qemu's mcimx6ul-evk (pinctrl-imx) with failslab injection while binding the pinctrl-consuming device, under KASAN: BUG: KASAN: double-free in dt_free_map+0x34/0xa4 Free of addr c425a900 by task init/1 kfree from dt_free_map+0x34/0xa4 dt_free_map from dt_remember_or_free_map+0x184/0x198 dt_remember_or_free_map from pinctrl_dt_to_map+0x33c/0x4c8 pinctrl_dt_to_map from create_pinctrl+0x9c/0x5c0 Initialize all dev_name fields to NULL before duplicating the device name, making the full-map cleanup safe after a partial failure.