crypto/ccp: Skip SNP_INIT if preparation fails

If snp_prepare() fails, SNP_INIT will fail, so skip it and return early.

Note that this is not a change in initialization behavior: if SNP_INIT fails
even before this change, it will still return an error and
__sev_snp_init_locked() will fail initialization of other SEV modes.

Signed-off-by: Tycho Andersen (AMD) <tycho@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Link: https://lore.kernel.org/20260429155636.540040-1-tycho@kernel.org

drivers/crypto/ccp/sev-dev.c

@@ -1374,7 +1374,9 @@ static int __sev_snp_init_locked(int *error, unsigned int max_snp_asid)
 		return -EOPNOTSUPP;
 	}
 
-	snp_prepare();
+	rc = snp_prepare();
+	if (rc)
+		return rc;
 
 	/*
 	 * Starting in SNP firmware v1.52, the SNP_INIT_EX command takes a list