sem_util.ads: Update comment describing function Deepest_Access_Level.

2011-11-21  Steve Baird  <baird@adacore.com>

	* sem_util.ads: Update comment describing function
	Deepest_Access_Level.
	* sem_util.adb (Deepest_Type_Access_Level): Return Int'Last for a
	generic formal type.
	(Type_Access_Level): Return library level
	for a generic formal type.
	* sem_attr.adb (Resolve_Attribute): Replace two Type_Access_Level
	calls with calls to Deepest_Type_Access_Level.
	* sem_ch3.adb (Analyze_Component_Declaration): replace a
	Type_Access_Level call with a call to Deepest_Type_Access_Level.
	* sem_res.adb (Resolve_Allocator.Check_Allocator_Discrim_Accessibility):
	Replace three Type_Access_Level calls with calls to
	Deepest_Type_Access_Level.
	(Resolve_Allocator): Replace a Type_Access_Level call with a call to
	Deepest_Type_Access_Level.
	(Valid_Conversion.Valid_Array_Conversion): Replace a
	Type_Access_Level call with a call to Deepest_Type_Access_Level.

From-SVN: r181570