sepolicy : correct the matching expression of sysfs_ssr

Current expression is unable to match all the name files of sysfs_ssr.
There are denials of sysfs files because of this. Correct it to fix
the denials.
CRs-Fixed: 2111501
Change-Id: I7786b34e10b36232186e55fb9cef8dcb5710d6a4