MIPS: octeon: Replace memset(0) + deprecated strcpy() with strscpy_pad()

MIPS: octeon: Replace memset(0) + deprecated strcpy() with strscpy_pad()

Replace memset(0) followed by the deprecated strcpy() with strscpy_pad()
to improve octeon_fdt_set_phy(). This avoids zeroing the memory before
copying the string and ensures the destination buffer is only written to
once, simplifying the code and improving efficiency.

Link: https://github.com/KSPP/linux/issues/88
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>