ipq806x: fix build errors on 6.12 kernel

ipq806x: fix build errors on 6.12 kernel

- Replace "strlcpy()" with "strscpy()".
- Convert platform driver .remove() to .remove_new().

This patch fixes the following compile errors:

drivers/of/fdt.c:1064:17: error: implicit declaration of function 'strlcpy'; did you mean 'strncpy'? [-Wimplicit-function-declaration]
 1064 |                 strlcpy(cmdline, p, min((int)l, COMMAND_LINE_SIZE));
      |                 ^~~~~~~
      |                 strncpy

drivers/devfreq/krait-cache-devfreq.c:171:27: error: initialization of 'void (*)(struct platform_device *)' from incompatible pointer type 'int (*)(struct platform_device *)' [-Wincompatible-pointer-types]
  171 |         .remove         = krait_cache_remove,
      |                           ^~~~~~~~~~~~~~~~~~

drivers/devfreq/ipq806x-fab-devfreq.c:145:27: error: initialization of 'void (*)(struct platform_device *)' from incompatible pointer type 'int (*)(struct platform_device *)' [-Wincompatible-pointer-types]
  145 |         .remove         = ipq806x_fab_remove,
      |                           ^~~~~~~~~~~~~~~~~~

Signed-off-by: Shiji Yang <yangshiji66@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/18989
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>