drm/amdkfd: fix gfx_target_version for certain 11.0.3 devices

Certain boards with GC IP 11.0.3 need slightly different handling
in the shader compiler due to board specific bounding box
optimizations.

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