x86/sev: Fix __reserved field in sev_config

sev_config currently has debug, ghcbs_initialized, and use_cas fields.
However, __reserved count has not been updated. Fix this.

Fixes: 34ff6590 ("x86/sev: Use kernel provided SVSM Calling Areas")
Signed-off-by: Pavan Kumar Paluri <papaluri@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240729180808.366587-1-papaluri@amd.com

arch/x86/coco/sev/core.c

@@ -163,7 +163,7 @@ struct sev_config {
 	       */
 	      use_cas		: 1,
 
-	      __reserved	: 62;
+	      __reserved	: 61;
 };
 
 static struct sev_config sev_cfg __read_mostly;