[fuchsia] Remove unused |target_staging_path| argument.

This argument has not been required since we migrated to publishing
packages to VMs & devices via 'pm'.

Bug: 895627
Change-Id: I972a2a40e7e655c8b4e0915f1868bfc31e549265
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1994919
Commit-Queue: Kevin Marshall <kmarshall@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Auto-Submit: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#730916}

build/fuchsia/run_package.py

@@ -120,19 +120,15 @@ class RunPackageArgs:
   symbolizer_config: A newline delimited list of source files contained
       in the package. Omitting this parameter will disable symbolization.
   system_logging: If set, connects a system log reader to the target.
-  target_staging_path: Path to which package FARs will be staged, during
-      installation. Defaults to staging into '/data'.
   """
   def __init__(self):
     self.symbolizer_config = None
     self.system_logging = False
-    self.target_staging_path = '/data'
 
   @staticmethod
   def FromCommonArgs(args):
     run_package_args = RunPackageArgs()
     run_package_args.system_logging = args.include_system_logs
-    run_package_args.target_staging_path = args.target_staging_path
     return run_package_args