Remove isDataspaceValid

isDataspaceValid is problematic in that it prevents
applications from being able to pass-through dataspaces
they receive from other APIs, and it also assumes that
the display's capabilities are the only things that are supported.

Although it's recommended that applications stick to dataspaces
that the display can handle, it's not strictly required. RenderEngine
can handle more dataspaces than the display can, applying appropriate
color conversion. Similarly this could be going to a virtual display
instead, in which case the physical display's capabilities are not
necessarily relevant.

Bug: 149931223
Test: make
Change-Id: I475f4e4dcbcdb4765670f6a8eb4cc047a9babb43