drm/amdkfd: Use huge page size to check split svm range alignment

drm/amdkfd: Use huge page size to check split svm range alignment

When split svm ranges that have been mapped using huge page should use huge
page size(2MB) to check split range alignment, not prange->granularity that
means migration granularity.

Fixes: 7ef6b2d4b7e5 ("drm/amdkfd: remap unaligned svm ranges that have split")
Signed-off-by: Xiaogang Chen <xiaogang.chen@amd.com>
Reviewed-by: Philip Yang <Philip.Yang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>