crypto: ccp - Add support for extended PSP mailbox commands

The PSP mailbox supports a number of extended sub-commands.  These
subcommands are placed in the header of the buffer sent to the mailbox.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>