[Ada] Remove redundant checks for non-empty list of aspects

[Pierre-Marie de Rodat]

Cleanup related to inlining-for-proof and detection of overlaying actual
parameters in GNATprove; semantics is unaffected.

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

gcc/ada/

        * inline.adb (Has_Excluded_Declaration): Remove redundant guard;
        the guarded code will call First on a No_List, which is
        well-defined and gives Empty.
diff --git a/gcc/ada/inline.adb b/gcc/ada/inline.adb
--- a/gcc/ada/inline.adb
+++ b/gcc/ada/inline.adb
@@ -4319,9 +4319,7 @@ package body Inline is
          --  functions, i.e. nested subprogram bodies, so inlining is not
          --  possible.
 
-         elsif Nkind (Decl) = N_Subtype_Declaration
-           and then Present (Aspect_Specifications (Decl))
-         then
+         elsif Nkind (Decl) = N_Subtype_Declaration then
             declare
                A    : Node_Id;
                A_Id : Aspect_Id;