drm/xe/xe_migrate: Cast to output precision before multiplying operands

In the Linux kernel, the following vulnerability has been resolved: drm/xe/xe_migrate: Cast to output precision before multiplying operands Addressing potential overflow in result of multiplication of two lower precision (u32) operands before widening it to higher precision (u64). -v2 Fix commit message and description. (Rodrigo) (cherry picked from commit 34820967ae7b45411f8f4f737c2d63b0c608e0d7)