Change mini-keyctl command format.

This CL change the mini-keyctl tool to make it compitable with libkeyctl
tool to make it more useful.

Bug: 112038861
Test: mini-keyctl padd asymmetric 'desc' .fs-verity < /path/to/cert.der
Test: mini-keyctl unlink <key_id> <keyring_id>
Test: mini-keyctl restrict_keyring <keyring_id>

Change-Id: I950f07c7718f173823ce5a5cd08e0d1a0e23a007