rpmb_dev: Switch to RPMB provisioning scheme

Remove the --key option part to disable the initial setting of rpmb key
on the mock rpmb device.
The RPMB provisioning scheme will program the RPMB key into the mock
rpmb device.

Bug: 152901318
Test: Trusty storage tests
Change-Id: I03b9cfbbd10e2e5364405319a57e2ecc4ee0f48e
diff --git a/trusty/utils/rpmb_dev/rpmb_dev.rc b/trusty/utils/rpmb_dev/rpmb_dev.rc
index 9f60e81..9e203b8 100644
--- a/trusty/utils/rpmb_dev/rpmb_dev.rc
+++ b/trusty/utils/rpmb_dev/rpmb_dev.rc
@@ -16,7 +16,7 @@
     disabled
     user root
 
-service rpmb_mock_init /vendor/bin/rpmb_dev --dev /data/vendor/ss/RPMB_DATA --init --key "ea df 64 44 ea 65 5d 1c 87 27 d4 20 71 0d 53 42 dd 73 a3 38 63 e1 d7 94 c3 72 a6 ea e0 64 64 e6" --size 2048
+service rpmb_mock_init /vendor/bin/rpmb_dev --dev /data/vendor/ss/RPMB_DATA --init --size 2048
     disabled
     user system
     group system