pw_hdlc_lite: Process read server packets

ReadAndProcessData() did an early return whenever a byte was
successfully read from pw::sys_io. This fixes the logic so that as long
as valid data is being read it will be processed by the server.

Change-Id: Ie75fe7a5d2f7987ed52e60c6d2f61dc3f279c494
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/18169
Reviewed-by: Wyatt Hepler <hepler@google.com>
Commit-Queue: Armando Montanez <amontanez@google.com>
diff --git a/pw_hdlc_lite/public/pw_hdlc_lite/rpc_server_packets.h b/pw_hdlc_lite/public/pw_hdlc_lite/rpc_server_packets.h
index 45b639e..5074594 100644
--- a/pw_hdlc_lite/public/pw_hdlc_lite/rpc_server_packets.h
+++ b/pw_hdlc_lite/public/pw_hdlc_lite/rpc_server_packets.h
@@ -39,7 +39,7 @@
   std::byte data;
 
   while (true) {
-    if (pw::sys_io::ReadByte(&data).ok()) {
+    if (!pw::sys_io::ReadByte(&data).ok()) {
       return;
     }
 
@@ -51,4 +51,4 @@
   }
 }
 
-}  // namespace pw::rpc
\ No newline at end of file
+}  // namespace pw::rpc