doc: exclude sam3* completely from doxygen

Also remove doc.txt for sam3 (moved to cpu_conf.h)

cpu/sam3/doc.txt

-/**
- * @defgroup        cpu_sam3 Atmel SAM3X8E
- * @ingroup         cpu
- * @brief           Atmel SAM3X8E Cortex-M3 MCU specific code
- */
-
-/**
- * @defgroup        cpu_sam3x8e_definitions Atmel SAM3X8E Definitions
- * @ingroup         cpu_sam3x8e
- */

cpu/sam3/include/cpu_conf.h

@@ -7,7 +7,9 @@
  */
 
 /**
- * @ingroup         cpu_sam3
+ * @defgroup        cpu_sam3 Atmel SAM3X8E
+ * @ingroup         cpu
+ * @brief           Atmel SAM3X8E Cortex-M3 MCU specific code
  * @{
  *
  * @file

cpu/sam3/include/sam3x8e/component/doc.txt

-/**
- * @defgroup    cpu_sam3x8e_components SAM3XA Components
- * @brief       SAM3XA Components
- * @ingroup     cpu_sam3x8e
- */

doc/doxygen/riot.doxyfile

@@ -816,7 +816,7 @@ EXCLUDE_PATTERNS       = */board/*/tools/* \
                          */cpu/*/include/instance/* \
                          */cpu/*/include/pio/* \
                          */cpu/*/include/atmel/* \
-                         */cpu/sam3/include/sam3*.h \
+                         */cpu/sam3/include/sam3* \
                          */cpu/sam3/include/system_sam*.h \
                          */cpu/lpc*/include/core_cm*.h \
                          */cpu/cortexm_common/include/core_cm*.h \