Additional path - followup to #4743

Marlin/Makefile

 VPATH += $(HARDWARE_DIR)/marlin/avr/libraries/LiquidCrystal/src
 VPATH += $(HARDWARE_DIR)/marlin/avr/libraries/SPI
 VPATH += $(HARDWARE_DIR)/arduino/avr/libraries/SPI
+VPATH += $(HARDWARE_DIR)/arduino/avr/libraries/SPI/src
 VPATH += $(ARDUINO_INSTALL_DIR)/libraries/LiquidCrystal/src
 ifeq ($(LIQUID_TWI2), 1)
 VPATH += $(ARDUINO_INSTALL_DIR)/libraries/Wire