anv: fix pipeline flag fields
What does this MR do and why?
anv: fix pipeline flag fields
Using the wrong type truncate the top bits of the pipeline flags.
Currently we don't have any bit in the top bits so not fixing any bug,
but in the future new extension could add some.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 688bb37552 ("anv: deal with new pipeline flags")