swrast: Drop remaining use of _ReallyEnabled.

The _MaxEnabledTexImageUnit check assures us that Unit[0].Current != NULL.
This is the last consumer of _ReallyEnabled outside of the radeons.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

src/mesa/swrast/s_triangle.c

@@ -1072,7 +1072,7 @@ _swrast_choose_triangle( struct gl_context *ctx )
              && !_swrast_use_fragment_program(ctx)
              && !ctx->ATIFragmentShader._Enabled
              && ctx->Texture._MaxEnabledTexImageUnit == 0
-             && ctx->Texture.Unit[0]._ReallyEnabled == TEXTURE_2D_BIT
+             && ctx->Texture.Unit[0]._Current->Target == GL_TEXTURE_2D
              && samp->WrapS == GL_REPEAT
              && samp->WrapT == GL_REPEAT
              && texObj2D->_Swizzle == SWIZZLE_NOOP