i386/sev: Fix error message in sev_get_capabilities()

When a custom path is provided to sev-guest object and opening
the path fails an error message is reported. But the error
message still mentions DEFAULT_SEV_DEVICE ("/dev/sev") instead of
the custom path.

Fixes: 16dcf200dc951c1cde3e5b442457db5f690b8cf0
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/b4648905d399780063dc70851d3d6a3cd28719a5.1719218926.git.mprivozn@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/target/i386/sev.c b/target/i386/sev.c
index 2a0f94d..0543668 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -597,7 +597,7 @@
     fd = open(sev_device, O_RDWR);
     if (fd < 0) {
         error_setg_errno(errp, errno, "SEV: Failed to open %s",
-                         DEFAULT_SEV_DEVICE);
+                         sev_device);
         g_free(sev_device);
         return NULL;
     }