drm/amdgpu: enlarge maximum waiting time of KIQ

KIQ in VF’s init delayed by another VF’s reset,
which would cause late_init failed occasionally.
MAX_KIQ_REG_TRY enlarged from 20 to 80 would fix this issue.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Wentao Lou <Wentao.Lou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>