Docs: Removed GCP from trial options. (#667)

* Docs: Removed GCP from trial options.

* Implemented peer reviewer's feedback.

docs/kafka/getting-started-kafka/README.adoc

@@ -138,7 +138,7 @@ endif::[]
 . On the *Kafka Instances* page of the {product-kafka} {service-url-kafka}[web console^], click *Create Kafka instance*.
 . Complete the *Create a Kafka instance* form to define the following instance details. Some instance details currently have only one option.
 * *Instance name*: Enter a unique name for the Kafka instance, such as `my-first-kafka-instance`.
-* *Cloud provider*: For a production Kafka instance, accept the default value of *Amazon Web Services*. If you're creating a trial instance, you also have the option to select *Google Cloud Platform*.
+* *Cloud provider*: Accept the default value of *Amazon Web Services*. 
 * *Cloud region*: Select a cloud provider region from the list.
 * *Availability zones*: The selection for availability zones is preconfigured as *Multi* for a production instance and *Single* for a trial instance.
 * *Size*: If you've purchased a subscription for {product-kafka}, use the slider to select an instance size. In {product-kafka}, you can create Kafka instances of 1 or 2 streaming units depending on the capacity required. If you're creating a trial instance, the instance size is preconfigured.