i965/gen4: Fix crash with fragment programs and texture rectangle.

i965/gen4: Fix crash with fragment programs and texture rectangle.

This was a regression in the brw_fs_fp.cpp change.  We just need to return
something good enough to get the IR generation to the end without crashing,
but ir->type isn't initialized and we wanted something of the coordinate's
type anyway.

Fixes around 30 piglit cases on my ilk system in drawpixels and framebuffer
blit.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=56962
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>