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-yosemitev2/recipes-bsp/u-boot/u-boot-aspeed_%.bbappend b/meta-facebook/meta-yosemitev2/recipes-bsp/u-boot/u-boot-aspeed_%.bbappend
index 1c38b11..298738f 100644
--- a/meta-facebook/meta-yosemitev2/recipes-bsp/u-boot/u-boot-aspeed_%.bbappend
+++ b/meta-facebook/meta-yosemitev2/recipes-bsp/u-boot/u-boot-aspeed_%.bbappend
@@ -1,3 +1,3 @@
-FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+FILESEXTRAPATHS:prepend := "${THISDIR}/${PN}:"
 SRC_URI +="file://0001-board-aspeed-Add-Mux-for-yosemitev2.patch"
 SRC_URI +="file://0002-spl-host-console-handle.patch"