service/nvdrv: Use std::move where applicable

Avoids unnecessary reference count increments and decrements.

In one case, we don't need to make a shared_ptr copy at all,
just to call a member function.

src/core/hle/service/nvdrv/nvdrv.cpp

@@ -2,6 +2,8 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <utility>
+
 #include "core/hle/ipc_helpers.h"
 #include "core/hle/service/nvdrv/devices/nvdevice.h"
 #include "core/hle/service/nvdrv/devices/nvdisp_disp0.h"
@@ -45,9 +47,9 @@ u32 Module::Open(std::string device_name) {
                device_name);
 
     auto device = devices[device_name];
-    u32 fd = next_fd++;
+    const u32 fd = next_fd++;
 
-    open_files[fd] = device;
+    open_files[fd] = std::move(device);
 
     return fd;
 }
@@ -56,7 +58,7 @@ u32 Module::Ioctl(u32 fd, u32_le command, const std::vector<u8>& input, std::vec
     auto itr = open_files.find(fd);
     ASSERT_MSG(itr != open_files.end(), "Tried to talk to an invalid device");
 
-    auto device = itr->second;
+    auto& device = itr->second;
     return device->ioctl({command}, input, output);
 }