The idea was to defer that part to check_fbo_compat() for the FBO ORM
but, it turns out, there are formats like DXTn that aren't generally
FBO-attachable but still support sRGB.

Fixes 9fc3444d (it's a partial revert,
in fact).
Signed-off-by: Matteo Bruni <mbruni@codeweavers.com>
Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>