dio: Replace deprecated strcpy with strscpy in dio_init

dio: Replace deprecated strcpy with strscpy in dio_init

strcpy() has been deprecated [1] because it performs no bounds checking
on the destination buffer, which can lead to buffer overflows. While the
current code works correctly, replace strcpy() with the safer strscpy()
to follow secure coding best practices.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://patch.msgid.link/20260504081804.3260-3-thorsten.blum@linux.dev
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>