[Ada] Remove Initializes contracts from Ada.Strings.Bounded

gcc/ada/

	* libgnat/a-strbou.ads (Generic_Bounded_Length): Remove explicit
	Initializes contract.
diff --git a/gcc/ada/libgnat/a-strbou.ads b/gcc/ada/libgnat/a-strbou.ads
index cc24f70..31c1cc9 100644
--- a/gcc/ada/libgnat/a-strbou.ads
+++ b/gcc/ada/libgnat/a-strbou.ads
@@ -45,8 +45,6 @@
       --  Maximum length of a Bounded_String
 
    package Generic_Bounded_Length with SPARK_Mode,
-     Initializes       => (Null_Bounded_String => Max,
-                           Max_Length          => Max),
      Initial_Condition => Length (Null_Bounded_String) = 0,
      Abstract_State    => null
    is