gallium/ntt: Work around virglrenderer UIF handling bug.
Until just recently ("vrend: Fix TGSI UIF/IF behavior"), virgl does "if
(any(bvec4(src0)))" instead of "if (src0.x != 0)", despite the tgsi.rst
documentation and tgsi_exec agreeing on the second form. It's harmless to
work around it, since apparently NTT was the only one to not have scalar
swizzled the if condition.
Reviewed-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8373>