drm/amdkfd: remap unaligned svm ranges that have split

Split SVM ranges that have been mapped into 2MB page table entries,
require to be remap in case the split has happened in a non-aligned
VA.
[WHY]:
This condition causes the 2MB page table entries be split into 4KB
PTEs.

Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>