tdh8.py: fix driver bug - (2 of 3) - #11363

Partially filled memory names must be padded with 0x00. 0xFF is only
valid when the entire name field is empty (but 0x00 is acceptable as
well).

chirp/drivers/tdh8.py

@@ -1342,7 +1342,7 @@ def set_memory(self, mem):
             try:
                 _nam.name[i] = mem.name[i]
             except IndexError:
-                _nam.name[i] = "\xFF"
+                _nam.name[i] = "\x00"
 
         txtone, rxtone = chirp_common.split_tone_encode(mem)