crypto: ccp: Implement SEV_PDH_GEN ioctl command

The SEV_PDH_GEN command is used to re-generate the Platform
Diffie-Hellman (PDH) key. The command is defined in SEV spec section
5.6.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Gary Hook <gary.hook@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-crypto@vger.kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Gary R Hook <gary.hook@amd.com>

drivers/crypto/ccp/psp-dev.c

@@ -333,6 +333,9 @@ static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 	case SEV_PEK_GEN:
 		ret = sev_ioctl_do_pek_pdh_gen(SEV_CMD_PEK_GEN, &input);
 		break;
+	case SEV_PDH_GEN:
+		ret = sev_ioctl_do_pek_pdh_gen(SEV_CMD_PDH_GEN, &input);
+		break;
 	default:
 		ret = -EINVAL;
 		goto out;