cmd: Add dtimg command

dtimg command allows user to work with Android DTB/DTBO image format.
Such as, getting the address of desired DTB/DTBO file, printing the dump
of the image in U-Boot shell, etc.

This command is needed to provide Android boot with new Android DT image
format further.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/cmd/Makefile b/cmd/Makefile
index 12d2118..b1206fc 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -43,6 +43,7 @@
 obj-$(CONFIG_CMD_DIAG) += diag.o
 endif
 obj-$(CONFIG_CMD_DISPLAY) += display.o
+obj-$(CONFIG_CMD_DTIMG) += dtimg.o
 obj-$(CONFIG_CMD_ECHO) += echo.o
 obj-$(CONFIG_ENV_IS_IN_EEPROM) += eeprom.o
 obj-$(CONFIG_CMD_EEPROM) += eeprom.o