VOL-576: asfvolt16 upgrade driver framework to BAL 2.4.7.12 release

Fixed default patch file name in BAL prepare script

Change-Id: I8d983df9fbce3262401c62dc00c7b560ea94b21d
diff --git a/scripts/asfvolt-bal-prepare.sh b/scripts/asfvolt-bal-prepare.sh
index befbff8..14bbd6d 100755
--- a/scripts/asfvolt-bal-prepare.sh
+++ b/scripts/asfvolt-bal-prepare.sh
@@ -28,7 +28,7 @@
 : ${BROADCOM_DOWNLOAD_DIR:=${HOME}/broadcom/download}  # directory containing SW-BCM68620_2_4_x.zip
 : ${EDGECORE_DOWNLOAD_DIR:=${HOME}/edgecore/download}  # directory containing ASFvOLT16 patch file for BAL
 
-: ${PATCH_FILENAME:=ACCTON_BAL_2.4.3.6-V201710131639.patch}   # use latest known ASFvOLT16 patch file as default
+: ${PATCH_FILENAME:=ACCTON_BAL_2.4.7.12-V201712061142.patch}   # use latest known ASFvOLT16 patch file as default
 
 echo ONL_TOPDIR=${ONL_TOPDIR}
 echo BALSRC_RELEASE=${BALSRC_RELEASE}