bsps: Adjust architecture Doxygen groups

- Use CamelCase as it is not used in our C code.  Enables simple search and
   replace.

 - Prefix with "RTEMS" to aid deployment and integration.  It aids
   searching and sorting.

Update #3706.

bsps/arm/shared/doxygen.h

@@ -1,15 +1,15 @@
-  /**
-  *  @defgroup bsp_arm ARM
-  *
-  *  @ingroup bsp_kit
-  *
-  *  @brief ARM Board Support Packages
-  */
+/**
+ * @defgroup RTEMSBSPsARM ARM
+ *
+ * @ingroup RTEMSBSPs
+ *
+ * @brief ARM Board Support Packages.
+ */
 
  /**
   *  @defgroup arm_shared ARM Shared Modules
   *
-  *  @ingroup bsp_arm
+  *  @ingroup RTEMSBSPsARM
   *
   *  @brief ARM Shared Modules
   */