Remove indirection of cpufeatures.gypi.

Now that android_webview_build is no longer supported, the extra level
of indirection of including cpufeatures.gypi is no longer necessary.
Depend on the target directly instead.

BUG=chromium:440793
R=andrew@webrtc.org, rtoy@google.com

Review URL: https://webrtc-codereview.appspot.com/48899004
diff --git a/dl/dl.gyp b/dl/dl.gyp
index f5a3aee..37e94a7 100644
--- a/dl/dl.gyp
+++ b/dl/dl.gyp
@@ -204,8 +204,8 @@
           'conditions': [
             ['arm_neon_optional==1', {
               # Run-time NEON detection.
-              'includes': [
-                '../../../build/android/cpufeatures.gypi',
+              'dependencies': [
+                '../../../build/android/ndk.gyp:cpu_features',
               ],
               'link_settings' : {
                 'libraries': [