Vulkan: Remove a call to addReadDependency() that shouldn't be done.

Bug: angleproject:3798
Change-Id: I516e6b0766ba0fe7c0bc7f6cd9f4aea91c7536f1
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1745839
Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Ian Elliott <ianelliott@google.com>

src/libANGLE/renderer/vulkan/TextureVk.cpp

@@ -434,7 +434,6 @@ angle::Result TextureVk::copySubImageImpl(const gl::Context *context,
         framebufferVk));
     onStagingBufferChange();
 
-    framebufferVk->getFramebuffer()->addReadDependency(mImage);
     return angle::Result::Continue;
 }