sepolicy: Policy fix for rpmb partition

On 4.19 kernel, due to upstream commit <97548575be>
(mmc: block: Convert RPMB to a character device),
Block device design for RPMB is now changed to char device.
This change add required permissions for qseecom daemon to
be able to access new device design for RPMB eMMC device.

Change-Id: I77a4ffc2107e61f66fe75cd2ccdc4d8da2685523