Require sdcard_type access to be explicitly allowed to
each domain.  This is to both protect services from
being killed by unsafe ejection and to protect SDcard
data from access by rogue daemons.

Change-Id: If3bdd50fd2be50bd98d755b2f252e0ae455b82c4
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>