crypto: ccp - Reset TMR size at SNP Shutdown

Implicit SNP initialization as part of some SNP ioctls modify TMR size
to be SNP compliant which followed by SNP shutdown will leave the
TMR size modified and then subsequently cause SEV only initialization
to fail, hence, reset TMR size to default at SNP Shutdown.

Acked-by: Dionna Glaze <dionnaglaze@google.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/ccp/sev-dev.c

@@ -1778,6 +1778,9 @@ static int __sev_snp_shutdown_locked(int *error, bool panic)
 	sev->snp_initialized = false;
 	dev_dbg(sev->dev, "SEV-SNP firmware shutdown\n");
 
+	/* Reset TMR size back to default */
+	sev_es_tmr_size = SEV_TMR_SIZE;
+
 	return ret;
 }