Merge pull request KhronosGroup#933 from gmlueck/gmlueck/platform-context

Removing contradictory statement about context

Author: gmlueck

adoc/chapters/architecture.adoc

@@ -154,8 +154,6 @@ When a group of devices can be grouped together on the same context, they have
 some visibility of each other's memory objects.
 The SYCL runtime can assume that memory is visible across all devices in the
 same <<context>>.
-Not all devices exposed from the same <<platform>> can be grouped together in
-the same <<context>>.
 
 A SYCL application executes on the host as a standard {cpp} program.
 <<device,Devices>> are exposed through different <<backend, SYCL backends>> to