[AMDGPU][MC][GFX11] Always output wait_vdst and wait_exp (#66610)

Always output values of wait_vdst and wait_exp in assembly even when
they are zero.

While we normally avoid outputing default/zero parameters in assembly,
the values of these parameters still imply wait behaviour when zero.
Outputing zero values makes the intent more obvious to human readers,
and avoid any future ambiguity if we choose to change the defaults to
something other than zero.

Fixes #66383