Fix compiler warnings:

sketch/Marlin_main.cpp:8756:8: warning: unused variable 'x_rec' [-Wunused-variable]
sketch/Marlin_main.cpp:8756:15: warning: unused variable 'y_rec' [-Wunused-variable]
sketch/Marlin_main.cpp:8756:22: warning: unused variable 'z_pos' [-Wunused-variable]

Firmware/Marlin_main.cpp

@@ -8753,7 +8753,6 @@ void recover_machine_state_after_power_panic(bool bTiny)
 }
 
 void restore_print_from_eeprom() {
-	float x_rec, y_rec, z_pos;
 	int feedrate_rec;
 	uint8_t fan_speed_rec;
 	char cmd[30];