i965: Set the fast clear color value for texture surfaces

i965: Set the fast clear color value for texture surfaces

When a multisampled texture is used for sampling the fast clear color value
needs to be programmed into the surface state. This was being left as all
zeroes so if the surface was cleared to a value other than black then it
wouldn't work properly. This doesn't matter for single-sample textures because
in that case the MCS buffer is resolved before it is used as a texture source.

https://bugs.freedesktop.org/show_bug.cgi?id=79729

Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Cc: "10.1 10.2" <mesa-stable@lists.freedesktop.org>