Fix bug with makeColorSpace of GPU images with non-renderable configs

A few GMs that draw Gray8 images found this on the gbr-gl config.

Bug: skia:
Change-Id: Iadeb21717d4d1daa48b85e08c45b1d058c2fe1b7
Reviewed-on: https://skia-review.googlesource.com/c/162282
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>

src/image/SkImage_GpuBase.cpp

@@ -263,7 +263,7 @@ sk_sp<SkImage> SkImage_GpuBase::onMakeColorSpace(sk_sp<SkColorSpace> target) con
     sk_sp<GrTextureProxy> proxy = this->asTextureProxyRef();
 
     sk_sp<GrRenderTargetContext> renderTargetContext(
-        fContext->contextPriv().makeDeferredRenderTargetContext(
+        fContext->contextPriv().makeDeferredRenderTargetContextWithFallback(
             SkBackingFit::kExact, this->width(), this->height(), proxy->config(), nullptr));
     if (!renderTargetContext) {
         return nullptr;