lib/gnat: Remove Compiler_Unit_Warning pragmas

'pragma Compiler_Unit_Warning' is removed upstream:
https://gcc.gnu.org/git/?p=gcc.git&a=search&h=HEAD&st=commit&s=pragma+Compiler_Unit_Warning

Fix:
    GCC        libgnat-x86_32/lib/gnat/interfac.o
interfac.ads:36:08: warning: unrecognized pragma "Compiler_Unit_Warning" [-gnatwg]

Change-Id: I6d7efab132441dd3cc62a53b7322e9fd355e5059
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73162
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <felixsinger@posteo.net>

src/lib/gnat/interfac.ads

@@ -33,8 +33,6 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-pragma Compiler_Unit_Warning;
-
 package Interfaces is
    pragma Pure;
 

src/lib/gnat/s-imenne.adb

@@ -29,7 +29,6 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-pragma Compiler_Unit_Warning;
 pragma Assertion_Policy (Statement_Assertions => Ignore);
 
 with Ada.Unchecked_Conversion;

src/lib/gnat/s-imenne.ads

@@ -40,8 +40,6 @@
 --  for bootstrapping with older versions of the compiler which expect to find
 --  functions in this package.
 
-pragma Compiler_Unit_Warning;
-
 package System.Img_Enum_New is
    pragma Pure;
 

src/lib/gnat/s-parame.ads

@@ -46,8 +46,6 @@
 --  Note: do not introduce any pragma Inline statements into this unit, since
 --  otherwise the relinking and rebinding capability would be deactivated.
 
-pragma Compiler_Unit_Warning;
-
 package System.Parameters is
    pragma Pure;
 

src/lib/gnat/s-stoele.adb

@@ -29,8 +29,6 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
-pragma Compiler_Unit_Warning;
-
 with Ada.Unchecked_Conversion;
 
 package body System.Storage_Elements is

src/lib/gnat/s-stoele.ads

@@ -37,8 +37,6 @@
 --  extra declarations that can be introduced into System using Extend_System.
 --  It is a good idea to avoid use clauses for this package.
 
-pragma Compiler_Unit_Warning;
-
 package System.Storage_Elements is
    pragma Pure;
    --  Note that we take advantage of the implementation permission to make

src/lib/gnat/s-unstyp.ads

@@ -35,8 +35,6 @@
 --  also contains some related definitions for other specialized types
 --  used by the compiler in connection with packed array types.
 
-pragma Compiler_Unit_Warning;
-
 package System.Unsigned_Types is
    pragma Pure;