tgsi_to_nir: Fix TGSI LIT translation by using flt.

tgsi_to_nir: Fix TGSI LIT translation by using flt.

TGSI spec says LIT needs a "greater than" comparison. NIR doesn't have that,
so let's use "less than" and swap the arguments. Previously "greater than or equal"
was used by tgsi_to_nir which is incorrect.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Tested-by: Andre Heider <a.heider@gmail.com>
Tested-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Eric Anholt <eric@anholt.net>