enrc2b: Remove SELinux policy files

Policy files are now in tegra3-common.

Device specific rules can still be added by placing files in the selinux
folder and by extending BOARD_SEPOLICY_UNION for new files.

Change-Id: I90238ba044b8e694f35a6c9a52b1310a00eec9e0
enrc2b: Import init.tegra3-common.rc

Change-Id: Id43c0f79843b06387400720ba0856989301ab53c