sepolicy: Update paths for daemons and ramdump daemon sepolicy

- qcomsysd/ssr_setup/ssr_diag/subsystem_ramdump are now part of the
vendor image. Update the file_contexts to reflect the same.
- Update the policy for the ssr_ramdump daemon to allow it to read
  from the enable_ramdump sysfs node.

Change-Id: I191cf0ba6ca5b96199cdf7e5dfc2fa1c042b8511