Revert "ls2080ardb: remove dhcp function from env as boot source"

dhcp boot is a useful feature and works out-of-the-box for ls2088a
platforms. Moreover, no solid reason is given for disabling it.
Revert the patch to re-enable it.

This reverts commit aea5cd75e63c20de4c00ce24a93eeee8542f923e.

Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
diff --git a/include/configs/ls2080ardb.h b/include/configs/ls2080ardb.h
index ef0f4ff..d3d7595 100644
--- a/include/configs/ls2080ardb.h
+++ b/include/configs/ls2080ardb.h
@@ -333,7 +333,8 @@
 #define BOOT_TARGET_DEVICES(func) \
 	func(USB, usb, 0) \
 	func(MMC, mmc, 0) \
-	func(SCSI, scsi, 0)
+	func(SCSI, scsi, 0) \
+	func(DHCP, dhcp, na)
 #include <config_distro_bootcmd.h>
 
 #ifdef CONFIG_TFABOOT