[cpu/arm] Added doxygen .txt files for gaining a minimum of documentation structure

cpu/arm/arm.txt

@@ -0,0 +1,19 @@
+/**
+ * @defgroup cmsis CMSIS (Cortex Microcontroller Software Interface Standard)
+ * @ingroup arm
+ */
+
+/**
+ * @defgroup aducrf101 ADUCRF101
+ * @ingroup arm
+ */
+
+/**
+ * @defgroup at91sam7s AT91SAM7S
+ * @ingroup arm
+ */
+
+/**
+ * @defgroup stm32f103 STM32F103
+ * @ingroup arm
+ */

cpu/arm/common/CMSIS/core.txt

@@ -0,0 +1,50 @@
+/**
+ * @addtogroup  CMSIS_Core_FunctionInterface
+ * @ingroup     cmsis
+ */
+
+/**
+ * @addtogroup    CMSIS_core_register
+ * @ingroup     cmsis
+ */
+
+/**
+ * @addtogroup    CMSIS_glob_defs
+ * @ingroup     cmsis
+ */
+
+/**
+ * @addtogroup    CMSIS_MISRA_Exceptions
+ * @ingroup     cmsis
+ */
+
+/**
+ * @addtogroup    CMSIS_core_definitions
+ * @ingroup     cmsis
+ */
+
+/**
+ * @addtogroup    CMSIS_SIMD_intrinsics
+ * @ingroup     cmsis
+ */
+
+/**
+ * @addtogroup    CMSIS_Core_InstructionInterface
+ * @ingroup     cmsis
+ */
+
+/**
+ * @defgroup Cortex_M0
+ * @ingroup cmsis
+ */
+
+/**
+ * @defgroup Cortex_M3
+ * @ingroup cmsis
+ */
+
+/**
+ * @defgroup Cortex_M4
+ * @ingroup cmsis
+ */
+