Do not allow lcd_updatestatus to be called directly

Enfoce the usage of lcd_setalertstatuspgm and lcd_setstatus so what we
consistently have alert severities properly set.

Firmware/temperature.cpp

@@ -1626,12 +1626,12 @@ public:
 			last_alert_sent_to_lcd = LCDALERT_MINTEMPFIXED;
 			break;
 		case States::ShowPleaseRestart: // displaying "Please restart"
-			lcd_updatestatuspgm(m1);
+			lcd_setalertstatuspgm(m1);
 			substep(States::ShowMintemp);
 			last_alert_sent_to_lcd = LCDALERT_PLEASERESTART;
 			break;
 		case States::ShowMintemp: // displaying "MINTEMP fixed"
-			lcd_updatestatuspgm(m2);
+			lcd_setalertstatuspgm(m2);
 			substep(States::ShowPleaseRestart);
 			last_alert_sent_to_lcd = LCDALERT_MINTEMPFIXED;
 			break;

Firmware/ultralcd.cpp

@@ -7956,7 +7956,7 @@ void lcd_setstatus(const char* message)
   lcd_updatestatus(message);
 }
 
-void lcd_updatestatuspgm(const char *message){
+static void lcd_updatestatuspgm(const char *message){
 	strncpy_P(lcd_status_message, message, LCD_WIDTH);
 	lcd_status_message[LCD_WIDTH] = 0;
 	lcd_finishstatus();
@@ -7971,7 +7971,8 @@ void lcd_setstatuspgm(const char* message)
   lcd_updatestatuspgm(message);
 }
 
-void lcd_updatestatus(const char *message){
+static void lcd_updatestatus(const char *message)
+{
 	strncpy(lcd_status_message, message, LCD_WIDTH);
 	lcd_status_message[LCD_WIDTH] = 0;
 	lcd_finishstatus();

Firmware/ultralcd.h

@@ -25,13 +25,10 @@ void lcd_setstatuspgm(const char* message);
 void lcd_setalertstatus(const char* message, uint8_t severity = LCD_STATUS_ALERT);
 void lcd_setalertstatuspgm(const char* message, uint8_t severity = LCD_STATUS_ALERT);
 
-//! only update the alert message on the main status screen
-//! has no sideeffects, may be called multiple times
-void lcd_updatestatus(const char *message);
-void lcd_updatestatuspgm(const char *message);
-
-void lcd_reset_alert_level();
+//! Get/reset the current alert level
 uint8_t get_message_level();
+void lcd_reset_alert_level();
+
 void lcd_adjust_z();
 void lcd_pick_babystep();
 void lcd_alright();