u-boot: Move recipes to the Aspeed BSP layer

Move the u-boot recipes out of the Phosphor layer to the Aspeed layer.
When a SOC requires a specific u-boot tree, convention dictates the
BSP layer supporting the SOC includes recipes for that tree.

Tested: Built image and verified in witherspoon qemu
Change-Id: I4d5bade05566ae4cbcf5a2c637a1ed275c63ab36
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/common/recipes-bsp/u-boot/u-boot_2016.07.bb b/common/recipes-bsp/u-boot/u-boot_2016.07.bb
new file mode 100644
index 0000000..0df7f2b
--- /dev/null
+++ b/common/recipes-bsp/u-boot/u-boot_2016.07.bb
@@ -0,0 +1,4 @@
+require recipes-bsp/u-boot/u-boot.inc
+require u-boot-common.inc
+
+DEPENDS += "dtc-native"