There are no more uses of SwiftShader's legacy OpenGL ES implementation
in AOSP. Arm Fixed Virtual Platforms (FVP) was the last to switch over
to using SwANGLE instead.

The build targets were already disabled, so this change removes them and
any exclusive dependencies, leaving only the Vulkan build.

Bug: b/147516027
Change-Id: Iabde8cc18ca5cff6f4c639b4619677478f4aaede
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/55588
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Macnak <natsu@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>