cmd: Add axi command

Add a command to debug the AXI bus.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/cmd/Makefile b/cmd/Makefile
index 323f1fd..12d2118 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -149,6 +149,7 @@
 obj-$(CONFIG_CMD_DFU) += dfu.o
 obj-$(CONFIG_CMD_GPT) += gpt.o
 obj-$(CONFIG_CMD_ETHSW) += ethsw.o
+obj-$(CONFIG_CMD_AXI) += axi.o
 
 # Power
 obj-$(CONFIG_CMD_PMIC) += pmic.o