Rename device access functions

Rename functions that access devices to reflect the derived device
they return. This includes the base device::Device and the derived
gpu/pal/roc device classes in both NullDevice and Device forms. Change
to use the least derived versions to clarify what operations will be
available.

Change-Id: I1abb6bfed7efa24852bc8d0d49acaea357d8b5d0

rocclr/device/devkernel.hpp

@@ -407,7 +407,7 @@ class Kernel : public amd::HeapObject {
   };
 
   //! Returns GPU device object, associated with this kernel
-  const amd::Device& dev() const { return dev_; }
+  const amd::Device& device() const { return dev_; }
 
   void setVecTypeHint(const std::string& hint) { workGroupInfo_.compileVecTypeHint_ = hint; }