Turn off NEON SkBoxBlurGetPlatformProcs for ARM64 (for now)

BUG=skia:2845
R=djsollen@google.com, senorblanco@google.com, senorblanco@chromium.org

Author: halcanary@google.com

Review URL: https://codereview.chromium.org/491973002
diff --git a/src/opts/SkBlurImage_opts_arm.cpp b/src/opts/SkBlurImage_opts_arm.cpp
index 10d595a..7462e6f 100644
--- a/src/opts/SkBlurImage_opts_arm.cpp
+++ b/src/opts/SkBlurImage_opts_arm.cpp
@@ -14,6 +14,8 @@
                                SkBoxBlurProc* boxBlurYX) {
 #if SK_ARM_NEON_IS_NONE
     return false;
+#elif defined(SK_CPU_ARM64)  // Temporary fix for
+    return false;            // http://skbug.com/2845
 #else
 #if SK_ARM_NEON_IS_DYNAMIC
     if (!sk_cpu_arm_has_neon()) {