meta-facebook: prep for new override syntax

Ran `scripts/contrib/convert-overrides.py` from upstream Yocto and
fixed up a few by hand that were missed.

Tested: Built bletchley and tiogapass.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I0489ba007132901697e4ef1a29b03a3591b3ee3b
diff --git a/meta-facebook/meta-bletchley/recipes-bsp/u-boot/u-boot-fw-utils-aspeed-sdk_%.bbappend b/meta-facebook/meta-bletchley/recipes-bsp/u-boot/u-boot-fw-utils-aspeed-sdk_%.bbappend
index b7bdbd2..c9401d1 100644
--- a/meta-facebook/meta-bletchley/recipes-bsp/u-boot/u-boot-fw-utils-aspeed-sdk_%.bbappend
+++ b/meta-facebook/meta-bletchley/recipes-bsp/u-boot/u-boot-fw-utils-aspeed-sdk_%.bbappend
@@ -1,4 +1,4 @@
-FILESEXTRAPATHS_prepend := "${THISDIR}/u-boot-aspeed-sdk:"
+FILESEXTRAPATHS:prepend := "${THISDIR}/u-boot-aspeed-sdk:"
 
 SRC_URI += " \
             file://0001-u-boot-ast2600-57600-baudrate-for-bletchley.patch \