rename TUSB_CFG_OS_TICKS_PER_SECOND to TUSB_CFG_TICKS_HZ

remove CFG_TICKS_PER_SECOND

demos/host/src/main.c

@@ -152,7 +152,7 @@ void print_greeting(void)
 --------------------------------------------------------------------\n"
   );
 
-  puts("This demo supports the following classes");
+  puts("This demo supports the following classes for HOST");
   if (TUSB_CFG_HOST_HUB          ) puts("  - Hub (1 level only)");
   if (TUSB_CFG_HOST_HID_MOUSE    ) puts("  - HID Mouse");
   if (TUSB_CFG_HOST_HID_KEYBOARD ) puts("  - HID Keyboard");