lib: Add atmel same51 and same54 build definitions

This also replaces the samd51 component files with the definitions
from the same54 repository.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

lib/same54/include/sam.h

@@ -0,0 +1,46 @@
+/**
+ * \file
+ *
+ * \brief Top level header file
+ *
+ * Copyright (c) 2019 Microchip Technology Inc.
+ *
+ * \license_start
+ *
+ * \page License
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * \license_stop
+ *
+ */
+
+#ifndef _SAM_
+#define _SAM_
+
+#if   defined(__SAME54N19A__) || defined(__ATSAME54N19A__)
+  #include "same54n19a.h"
+#elif defined(__SAME54N20A__) || defined(__ATSAME54N20A__)
+  #include "same54n20a.h"
+#elif defined(__SAME54P19A__) || defined(__ATSAME54P19A__)
+  #include "same54p19a.h"
+#elif defined(__SAME54P20A__) || defined(__ATSAME54P20A__)
+  #include "same54p20a.h"
+#else
+  #error Library does not support the specified device
+#endif
+
+#endif /* _SAM_ */
+