Add missing cmd_ximg.o to common/Makefile

Signed-off-by: Marian Balakowicz <m8@semihalf.com>

common/Makefile

@@ -89,6 +89,7 @@ COBJS-$(CONFIG_CMD_SPI) += cmd_spi.o
 COBJS-$(CONFIG_CMD_TERMINAL) += cmd_terminal.o
 COBJS-$(CONFIG_CMD_UNIVERSE) += cmd_universe.o
 COBJS-$(CONFIG_CMD_USB) += cmd_usb.o
+COBJS-$(CONFIG_CMD_XIMG) += cmd_ximg.o
 COBJS-y += cmd_vfd.o
 COBJS-y += command.o
 COBJS-y += console.o