[lldb] Fix FreeBSD Arm Process Plugin build.

[brooks]

Summary

Add a missing include and some definitions in rG769533216666.

lldb/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_arm.h

 //===-- RegisterContextPOSIXProcessMonitor_arm.h --------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef liblldb_RegisterContextPOSIXProcessMonitor_arm_H_
 #define liblldb_RegisterContextPOSIXProcessMonitor_arm_H_
 
 #include "Plugins/Process/Utility/RegisterContextPOSIX_arm.h"
 #include "RegisterContextPOSIX.h"
 
 class RegisterContextPOSIXProcessMonitor_arm : public RegisterContextPOSIX_arm,
                                                public POSIXBreakpointProtocol {
 public:
   RegisterContextPOSIXProcessMonitor_arm(
       lldb_private::Thread &thread,
       std::unique_ptr<RegisterInfoPOSIX_arm> register_info);
protected:
   bool IsWatchpointVacant(uint32_t hw_index);
 
   bool SetHardwareWatchpointWithIndex(lldb::addr_t addr, size_t size, bool read,
                                       bool write, uint32_t hw_index);
 
   uint32_t NumSupportedHardwareWatchpoints();
 
 private:
+  RegisterInfoPOSIX_arm::GPR m_gpr_arm;
+
+  RegisterInfoPOSIX_arm::FPU m_fpr;
+
   ProcessMonitor &GetMonitor();
 };
 
 #endif

lldb/source/Plugins/Process/FreeBSD/RegisterContextPOSIXProcessMonitor_arm.cpp

 //===-- RegisterContextPOSIXProcessMonitor_arm.cpp ------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===---------------------------------------------------------------------===//
 
 #include "lldb/Target/Thread.h"
 #include "lldb/Utility/DataBufferHeap.h"
 #include "lldb/Utility/RegisterValue.h"
 
 #include "ProcessFreeBSD.h"
 #include "ProcessMonitor.h"
 #include "RegisterContextPOSIXProcessMonitor_arm.h"
 #include "Plugins/Process/Utility/RegisterContextPOSIX_arm.h"
+#include "Plugins/Process/Utility/lldb-arm-register-enums.h"
 
 using namespace lldb_private;
 using namespace lldb;
 
 #define REG_CONTEXT_SIZE (GetGPRSize())
 
 RegisterContextPOSIXProcessMonitor_arm::RegisterContextPOSIXProcessMonitor_arm(
     lldb_private::Thread &thread,