crypto: ccp - Add SEV_INIT_EX support

crypto: ccp - Add SEV_INIT_EX support

Add new module parameter to allow users to use SEV_INIT_EX instead of
SEV_INIT. This helps users who lock their SPI bus to use the PSP for SEV
functionality. The 'init_ex_path' parameter defaults to NULL which means
the kernel will use SEV_INIT, if a path is specified SEV_INIT_EX will be
used with the data found at the path. On certain PSP commands this
file is written to as the PSP updates the NV memory region. Depending on
file system initialization this file open may fail during module init
but the CCP driver for SEV already has sufficient retries for platform
initialization. During normal operation of PSP system and SEV commands
if the PSP has not been initialized it is at run time. If the file at
'init_ex_path' does not exist the PSP will not be initialized. The user
must create the file prior to use with 32Kb of 0xFFs per spec.

Signed-off-by: David Rientjes <rientjes@google.com>
Co-developed-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Brijesh Singh <brijesh.singh@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Marc Orr <marcorr@google.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Rientjes <rientjes@google.com>
Cc: John Allen <john.allen@amd.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>