fix some doxygen settings and stuffs add prepacked for IAR compiler

tinyusb/common/compiler/compiler.h

@@ -53,6 +53,8 @@
 
 #if defined(__GNUC__)
   #include "compiler_gcc.h"
+#elif deinfed __ICCARM__ // IAR compiler
+  #include "compiler_iar.h"
 #endif
 
 #endif /* _TUSB_COMPILER_H_ */

tinyusb/common/compiler/compiler_gcc.h

@@ -37,8 +37,6 @@
 
 /** \file
  *  \brief GCC Header
- *
- *  \note TBD
  */
 
 /** \ingroup Group_Compiler
@@ -74,7 +72,6 @@
 #define ATTR_PACKED 							 __attribute__ ((packed))
 
 #define ATTR_PREPACKED
-#define ATTR_POSTPACKED            ATTR_PACKED
 /** @} */
 
 /** \ingroup Group_GCC