scons: Remove -Werror for the gem5 v23.0 release

While gem5 compiles on all our supported compilers, removing the -Werror
flag on the stable branch ensures that, as new compilers are released
with stricter warnings, gem5 remains compilable.

Change-Id: Ie32a5c526a17cc584bce3b71d27b8f052caf612b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/72178
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>

SConstruct

@@ -447,12 +447,6 @@ for variant_path in variant_paths:
                     conf.CheckLinkFlag(
                             '-Wl,--thread-count=%d' % GetOption('num_jobs'))
 
-        # Treat warnings as errors but white list some warnings that we
-        # want to allow (e.g., deprecation warnings).
-        env.Append(CCFLAGS=['-Werror',
-                             '-Wno-error=deprecated-declarations',
-                             '-Wno-error=deprecated',
-                            ])
 
     else:
         error('\n'.join((