GrGLGpu: Remove unused 'return'

We remove the last 'return' statement, which is never reached.
This makes it more clear at a glance what value is being
returned from the function.

Change-Id: Iedeb3f6783a45cb60cd4d1413e294fa025fd9651
Reviewed-on: https://skia-review.googlesource.com/c/191063
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

src/gpu/gl/GrGLGpu.cpp

@@ -1409,8 +1409,6 @@ bool GrGLGpu::uploadCompressedTexData(GrPixelConfig texConfig, int texWidth, int
     return allocate_and_populate_compressed_texture(texConfig, *interface, caps, target,
                                                     internalFormat, texels, mipLevelCount,
                                                     texWidth, texHeight);
-
-    return true;
 }
 
 static bool renderbuffer_storage_msaa(const GrGLContext& ctx,