GL_R11F_G11F_B10F is a color renderable format in OpenGL ES 3.0

GL_R11F_G11F_B10F is a color renderable format in OpenGL ES 3.0

GL_R11F_G11F_B10F was missing from a utility function, causing some
dEQP tests to fail. Simply adding it fixes most R11F_G11F_B10F
related tests in:
functional.fbo.*
functional.fragment_out.*
functional.pbo.*

Change-Id: I0d77f1c9c01aff106e266853e81b4cf45f748bc1
Reviewed-on: https://swiftshader-review.googlesource.com/11211
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>