[pa] disable registry buffer by default

The registry buffer service was removed, and will soon be replaced with
the proxybuffer service. However, the enablement flag within the PA was
still defaulting to true. This is updated to default to false until lowRISC#24
can be fixed.

Signed-off-by: Tim Trippel <[email protected]>

src/pa/pa_server.go

@@ -25,7 +25,7 @@ import (
 var (
 	port          = flag.Int("port", 0, "the port to bind the server on; required")
 	spmAddress    = flag.String("spm_address", "", "the SPM server address to connect to; required")
-	enableRegBuff = flag.Bool("enable_rb", true, "Enable connectivity to the RegistryBuffer server; optional")
+	enableRegBuff = flag.Bool("enable_rb", false, "Enable connectivity to the RegistryBuffer server; optional")
 	rbAddress     = flag.String("rb_address", "", "the RegistryBuffer server address to connect to; required")
 	enableTLS     = flag.Bool("enable_tls", false, "Enable mTLS secure channel; optional")
 	serviceKey    = flag.String("service_key", "", "File path to the PEM encoding of the server's private key")