[overnet] Remove std::forward on lvalue reference

llvm/llvm-project#120223 became more strict
about discarded value expressions. The current std::forward expressions
triggered a no-discard warning/error.

It seems like we can remove the `std::forward` on the lvalue reference
in these visitor functions anyway to resolve this error.

Fixed: 385748190
Change-Id: Iaf51848f82f0979f72a26736d33b50ad60738de4
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1179435
Commit-Queue: Auto-Submit <[email protected]>
Fuchsia-Auto-Submit: Caslyn Tonelli <[email protected]>
Reviewed-by: Casey Dahlin <[email protected]>

Author: Caslyn

src/connectivity/overnet/usb/overnet_usb.cc

@@ -327,7 +327,7 @@ void OvernetUsb::HandleSocketReadable(async_dispatcher_t*, async::WaitBase*, zx_
 
   std::visit(
       [this](auto& state) __TA_REQUIRES(lock_) {
-        if (std::forward<decltype(state)>(state).ReadsWaiting()) {
+        if (state.ReadsWaiting()) {
           ProcessReadsFromSocket();
         }
       },
@@ -366,7 +366,7 @@ void OvernetUsb::HandleSocketWritable(async_dispatcher_t*, async::WaitBase*, zx_
              std::move(state_));
   std::visit(
       [this](auto& state) __TA_REQUIRES(lock_) {
-        if (std::forward<decltype(state)>(state).WritesWaiting()) {
+        if (state.WritesWaiting()) {
           ProcessWritesToSocket();
         }
       },
@@ -610,14 +610,14 @@ void OvernetUsb::ReadComplete(fendpoint::Completion completion) {
         std::move(state_));
     std::visit(
         [this](auto& state) __TA_REQUIRES(lock_) {
-          if (std::forward<decltype(state)>(state).NewSocket()) {
+          if (state.NewSocket()) {
             auto request = PrepareTx();
 
             if (request) {
               SendMagicReply(std::move(*request));
             }
           }
-          if (std::forward<decltype(state)>(state).WritesWaiting()) {
+          if (state.WritesWaiting()) {
             ProcessWritesToSocket();
           }
         },