change lpc55s28 default port to 1

hw/bsp/lpc55/boards/lpcxpresso55s28/board.mk

@@ -2,6 +2,7 @@ MCU_VARIANT = LPC55S28
 MCU_CORE = LPC55S28
 
 CFLAGS += -DCPU_LPC55S28JBD100
+PORT ?= 1
 
 JLINK_DEVICE = LPC55S28
 PYOCD_TARGET = LPC55S28