drm/amdkfd: support larger svm range allocation

For larger range allocation, if hmm_range_fault return -EBUSY, set retry
timeout based on 1 second for every 512MB, this is safe timeout value.

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