Do not call reinitialize_more_filter from avr_io_reg_read_command

avr_io_reg_read_command is an ordinary gdb command, and so should not
be calling reinitialize_more_filter.  This patch removes it.  I'm
checking this in as obvious.  Tested by rebuilding.

gdb/avr-tdep.c

@@ -1589,8 +1589,6 @@ avr_io_reg_read_command (const char *args, int from_tty)
       return;
     }
 
-  reinitialize_more_filter ();
-
   printf_unfiltered (_("Target has %u io registers:\n\n"), nreg);
 
   /* only fetch up to 8 registers at a time to keep the buffer small */