drm/amdkfd: Set F8_MODE for gc_v9_4_3

Set F8_MODE for GC 9.4.3 as optimal/non-IEEE. Also update gc_v9_0
to gc_v9_4_3 to include more definitions such as the F8_MODE bit, and
remove unused header files.

v2: fix IP version check (Alex)

Signed-off-by: Amber Lin <Amber.Lin@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>