meson: remove needless c++17-overrides

C++17 is the project-wide default since f9057cea51 ("fix(FTBFS):
meson: raise C++ standard to C++17"), so let's drop these local
overrides.

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23048>

src/intel/compiler/meson.build

@@ -161,7 +161,6 @@ libintel_compiler = static_library(
   [libintel_compiler_files, brw_nir_trig, ir_expression_operation_h],
   include_directories : [inc_include, inc_src, inc_mapi, inc_mesa, inc_gallium, inc_intel],
   c_args : [no_override_init_args],
-  override_options: ['cpp_std=c++17'],
   gnu_symbol_visibility : 'hidden',
   dependencies : [idep_nir_headers, idep_mesautil, idep_intel_dev],
   build_by_default : false,
@@ -207,7 +206,6 @@ if with_tests
       link_with : [
         libintel_compiler, libintel_common, libisl
       ],
-      override_options: ['cpp_std=c++17'],
       dependencies : [idep_gtest, idep_nir, idep_mesautil, idep_intel_dev],
     ),
     suite : ['intel'],