[source] uboot-at91: move BUILD_SUBTARGET from U-Boot/Default to devices

[LEDE Commits]

blogic pushed a commit to source.git, branch master:
https://git.lede-project.org/71a93a22fdd52b363ec3ec8b59a68ceeb1c6beff

commit 71a93a22fdd52b363ec3ec8b59a68ceeb1c6beff
Author: Sandeep Sheriker Mallikarjun <sandeepsheriker.mallikarjun at microchip.com>
AuthorDate: Wed Sep 13 11:51:19 2017 -0700

    uboot-at91: move BUILD_SUBTARGET from U-Boot/Default to devices
    
    currenlty U-Boot/Default supports only at91 legacy devices.To add
    sama5 support, moving BUILD_SUBTARGET from U-Boot/Default to target
    devices.
    
    Signed-off-by: Sandeep Sheriker Mallikarjun <sandeepsheriker.mallikarjun at microchip.com>
---
 package/boot/uboot-at91/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/package/boot/uboot-at91/Makefile b/package/boot/uboot-at91/Makefile
index 6a806ff..68e4ba4 100644
--- a/package/boot/uboot-at91/Makefile
+++ b/package/boot/uboot-at91/Makefile
@@ -17,16 +17,17 @@ include $(INCLUDE_DIR)/package.mk
 
 define U-Boot/Default
   BUILD_TARGET:=at91
-  BUILD_SUBTARGET:=legacy
   UBOOT_IMAGE:=u-boot.bin boot.bin
 endef
 
 define U-Boot/at91sam9m10g45ek_nandflash
   NAME:=AT91SAM9M10G45-EK board (NandFlash)
+  BUILD_SUBTARGET:=legacy
 endef
 
 define U-Boot/at91sam9x5ek_nandflash
   NAME:=AT91SAM9X5-EK board (NandFlash)
+  BUILD_SUBTARGET:=legacy
 endef
 
 UBOOT_TARGETS := \