build_image: hard code set inode size to 256

inode-size will jump around based on filesystem size, however
readonly Android system partitions have a specific pattern of
xattr associated with sepolicy and 256 is the most efficient at
absorbing the content.

Test: manual
Bug: 122328872
Change-Id: I06dd6a503067ab6477293b386d56a89dd86b0e83

tools/releasetools/build_image.py

@@ -280,6 +280,7 @@ def BuildImageMkfs(in_dir, prop_dict, out_file, target_out, fs_config):
         build_command.extend(["-S", prop_dict["hash_seed"]])
     if "ext4_share_dup_blocks" in prop_dict:
       build_command.append("-c")
+    build_command.extend(["--inode_size", "256"])
     if "selinux_fc" in prop_dict:
       build_command.append(prop_dict["selinux_fc"])
   elif fs_type.startswith("squash"):