GSdx-d3d11: Redo destination format and alpha output.

Dfmt in texture shuffle function already picks the 16 format on slot 2
so it's better to let it call the shader instead of aout.

We can keep old aout code until FbMask emulation is added on d3d11. We
can purge aout along with alpha hack then.
Added fixme note.

plugins/GSdx/Renderers/DXCommon/GSRendererDX.cpp

@@ -583,14 +583,16 @@ void GSRendererDX::DrawPrims(GSTexture* rt, GSTexture* ds, GSTextureCache::Sourc
 	m_ps_sel.clr1 = m_om_bsel.IsCLR1();
 	m_ps_sel.fba = m_context->FBA.FBA;
 
+	// FIXME: Purge aout with AlphaHack when FbMask emulation is added.
 	if (m_ps_sel.shuffle)
 	{
 		m_ps_sel.aout = 0;
 	}
 	else
 	{
-		m_ps_sel.aout = UserHacks_AlphaHack || m_context->FRAME.PSM == PSM_PSMCT16 || m_context->FRAME.PSM == PSM_PSMCT16S || (m_context->FRAME.FBMSK & 0xff000000) == 0x7f000000 ? 1 : 0;
+		m_ps_sel.aout = UserHacks_AlphaHack || (m_context->FRAME.FBMSK & 0xff000000) == 0x7f000000;
 	}
+	// END OF FIXME
 
 	if (PRIM->FGE)
 	{