releasetools: fix avbtool arguments.

The following error occurred when building dist.
Separate these arguments

error log:
avbtool: error: unrecognized arguments: --partition_name vendor_boot

Bug: 144820089

Change-Id: I3891ef3bd9a2f7d2cd1377228b9894b599dc1cc3
Signed-off-by: Donghoon Yu <hoony.yu@samsung.com>
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 031db1d..23ef159 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -1241,7 +1241,7 @@
     avbtool = info_dict["avb_avbtool"]
     part_size = info_dict["vendor_boot_size"]
     cmd = [avbtool, "add_hash_footer", "--image", img.name,
-           "--partition_size", str(part_size), "--partition_name vendor_boot"]
+           "--partition_size", str(part_size), "--partition_name", "vendor_boot"]
     AppendAVBSigningArgs(cmd, "vendor_boot")
     args = info_dict.get("avb_vendor_boot_add_hash_footer_args")
     if args and args.strip():