u-boot: add u-boot-common.inc

Factor out variables needed by both fw-utils and the base recipe into a
common include.

u-boot.inc tried to do this but a number of ubi bootenv patches that
aren't needed by fw-utils were pulled in there.

Change-Id: Ia7006e620892030d05cb62cfb251143d0af54b42
Tested: Built witherspoon and palmetto images, verified u-boot, fw-utils
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/meta-phosphor/common/recipes-bsp/u-boot/u-boot_2016.07.bb b/meta-phosphor/common/recipes-bsp/u-boot/u-boot_2016.07.bb
index 2800623..bcb95fe 100644
--- a/meta-phosphor/common/recipes-bsp/u-boot/u-boot_2016.07.bb
+++ b/meta-phosphor/common/recipes-bsp/u-boot/u-boot_2016.07.bb
@@ -1,5 +1,5 @@
-LICENSE = "GPLv2+"
 require recipes-bsp/u-boot/u-boot.inc
+require u-boot-common.inc
 require u-boot.inc
 
 DEPENDS += "dtc-native"