[Ada] Avoid warnings regarding rep clauses in generics -- follow-on

[Pierre-Marie de Rodat via Gcc-patches]

Codepeer is complaining about uninitialized variables.  This fixes it.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

        * repinfo.adb (List_Component_Layout): Initialize Sbit.
diff --git a/gcc/ada/repinfo.adb b/gcc/ada/repinfo.adb
--- a/gcc/ada/repinfo.adb
+++ b/gcc/ada/repinfo.adb
@@ -1123,7 +1123,7 @@ package body Repinfo is
          Npos  : constant Uint := Normalized_Position (Ent);
          Fbit  : constant Uint := Normalized_First_Bit (Ent);
          Spos  : Uint;
-         Sbit  : Uint;
+         Sbit  : Uint := No_Uint;
          Lbit  : Uint;
 
       begin