Modify string format in BRILLO_VENDOR_PARTITIONS to preserve path.

BRILLO_VENDOR_PARTITIONS contains a list of strings in the format of
parent_folder:file_path. Each vendor partition's full path is
parent_folder/file_path. The directory structure in file_path will be preserved.

Bug: 25692226
TEST: local run m dist, confirm dragonboard-vendor_partitions-eng.dshi.zip
created in out/dist, and content is correct.

Change-Id: Icff46e4fa797cb6df7a2b8a651c6879c792cb60e
diff --git a/BoardConfig.mk b/BoardConfig.mk
index c00fb8d..952e412 100644
--- a/BoardConfig.mk
+++ b/BoardConfig.mk
@@ -31,21 +31,25 @@
     device/qcom/dragonboard/provision-device:provision-device
 
 vendor_partition_directory := vendor/bsp/qcom/device/dragonboard/qcom_410c_non-hlos_binaries_A8016BAAAAGLYD2131.1
+# BRILLO_VENDOR_PARTITIONS contains a list of strings in the format of
+# parent_directory:file_path. Each vendor partition's full path is
+# parent_directory/file_path. The directory structure in file_path will be
+# preserved.
 BRILLO_VENDOR_PARTITIONS := \
-  $(vendor_partition_directory)/partitions/misc.bin \
-  $(vendor_partition_directory)/partitions/partition-tables.bin \
-  $(vendor_partition_directory)/vendor_partitions/aboot.bin \
-  $(vendor_partition_directory)/vendor_partitions/DDR.bin \
-  $(vendor_partition_directory)/vendor_partitions/fsc.bin \
-  $(vendor_partition_directory)/vendor_partitions/fsg.bin \
-  $(vendor_partition_directory)/vendor_partitions/hyp.bin \
-  $(vendor_partition_directory)/vendor_partitions/modem.bin \
-  $(vendor_partition_directory)/vendor_partitions/modemst1.bin \
-  $(vendor_partition_directory)/vendor_partitions/modemst2.bin \
-  $(vendor_partition_directory)/vendor_partitions/rpm.bin \
-  $(vendor_partition_directory)/vendor_partitions/sbl1.bin \
-  $(vendor_partition_directory)/vendor_partitions/sec.bin \
-  $(vendor_partition_directory)/vendor_partitions/tz.bin
+  $(vendor_partition_directory):partitions/misc.bin \
+  $(vendor_partition_directory):partitions/partition-tables.bin \
+  $(vendor_partition_directory):vendor_partitions/aboot.bin \
+  $(vendor_partition_directory):vendor_partitions/DDR.bin \
+  $(vendor_partition_directory):vendor_partitions/fsc.bin \
+  $(vendor_partition_directory):vendor_partitions/fsg.bin \
+  $(vendor_partition_directory):vendor_partitions/hyp.bin \
+  $(vendor_partition_directory):vendor_partitions/modem.bin \
+  $(vendor_partition_directory):vendor_partitions/modemst1.bin \
+  $(vendor_partition_directory):vendor_partitions/modemst2.bin \
+  $(vendor_partition_directory):vendor_partitions/rpm.bin \
+  $(vendor_partition_directory):vendor_partitions/sbl1.bin \
+  $(vendor_partition_directory):vendor_partitions/sec.bin \
+  $(vendor_partition_directory):vendor_partitions/tz.bin
 
 BOARD_SEPOLICY_DIRS += \
     device/qcom/dragonboard/sepolicy