Remove MSG_M117_V2_CALIBRATION

This message is never actually shown on the LCD (it's immediately
overwritten by other content). It also include g-code in a translatable
string, which is not a good idea. It's also otherwise identical to
MSG_V2_CALIBRATION, which we should have used.

Just remove it and save some space in the process.

Firmware/first_lay_cal.cpp

@@ -14,27 +14,19 @@
 //! @brief Wait for preheat
 void lay1cal_wait_preheat()
 {
-    static const char cmd_preheat_0[] PROGMEM = "M107";
-    static const char cmd_preheat_1[] PROGMEM = "M190";
-    static const char cmd_preheat_2[] PROGMEM = "M109";
-    static const char cmd_preheat_4[] PROGMEM = "G28";
-    static const char cmd_preheat_5[] PROGMEM = "G92 E0.0";
-
     const char * const preheat_cmd[] =
     {
-        cmd_preheat_0,
-        cmd_preheat_1,
-        cmd_preheat_2,
-        _T(MSG_M117_V2_CALIBRATION),
-        cmd_preheat_4,
-        cmd_preheat_5,
+        PSTR("M107"),
+        PSTR("M190"),
+        PSTR("M109"),
+        PSTR("G28"),
+        PSTR("G92 E0.0")
     };
 
     for (uint8_t i = 0; i < (sizeof(preheat_cmd)/sizeof(preheat_cmd[0])); ++i)
     {
         enquecommand_P(preheat_cmd[i]);
     }
-
 }
 
 //! @brief Load filament

Firmware/messages.cpp

@@ -54,7 +54,6 @@ const char MSG_LOAD_FILAMENT[] PROGMEM_I1 = ISTR("Load filament"); ////MSG_LOAD_
 const char MSG_LOADING_FILAMENT[] PROGMEM_I1 = ISTR("Loading filament"); ////MSG_LOADING_FILAMENT c=20
 const char MSG_EJECT_FILAMENT[] PROGMEM_I1 = ISTR("Eject filament"); ////MSG_EJECT_FILAMENT c=17
 const char MSG_CUT_FILAMENT[] PROGMEM_I1 = ISTR("Cut filament"); ////MSG_CUT_FILAMENT c=17
-const char MSG_M117_V2_CALIBRATION[] PROGMEM_I1 = ISTR("M117 First layer cal."); ////MSG_M117_V2_CALIBRATION c=25
 const char MSG_MAIN[] PROGMEM_I1 = ISTR("Main"); ////MSG_MAIN c=18
 const char MSG_BACK[] PROGMEM_I1 = ISTR("Back"); ////MSG_BACK c=18
 const char MSG_SHEET[] PROGMEM_I1 = ISTR("Sheet"); ////MSG_SHEET c=10