chromium: Set use_vaapi=!stdenv.isAarch64 for M87

I've removed that option in 063b3699083 but forgot that M87 still
defaults to use_vaapi=false.

pkgs/applications/networking/browsers/chromium/common.nix

@@ -216,6 +216,7 @@ let
       is_official_build = true;
       is_debug = false;
 
+      use_vaapi = !stdenv.isAarch64; # TODO: Remove once M88 is released
       proprietary_codecs = false;
       use_sysroot = false;
       use_gnome_keyring = gnomeKeyringSupport;