Merge selinux fix to support in-core xattr of debufgs

Cherry pick from https://android-review.googlesource.com/#/c/123424/1

pstore: selinux: add security in-core xattr support for pstore and debugfs

- add "pstore" and "debugfs" to list of in-core exceptions
- change fstype checks to boolean equation
- change from strncmp to strcmp for checking

Signed-off-by: Mark Salyzyn <salyzyn@android.com>

BUG=26258202

Change-Id: I35b41660701fe63a5e8173813ac62b84474ec48f