anv: remove HDC flush from invalidate bits

This doesn't need to be in the invalidate bits.

This was hiding a missing restriction added in
5e21f474 ("anv: fixup PIPE_CONTROL
restriction on gfx8")

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: a49b145e ("anv: Replace DC Flush with HDC Pipeline Flush")