CVE-2026-46062: ntfs3: fix integer overflow in run_unpack() volume boundary check

In the Linux kernel, the following vulnerability has been resolved: ntfs3: fix integer overflow in run_unpack() volume boundary check The volume boundary check `lcn + len > sbi->used.bitmap.nbits` uses raw addition which can wrap around for large lcn and len values, bypassing the validation. Use check_add_overflow() as is already done for the adjacent prev_lcn + dlcn and vcn64 + len checks added by commit 3ac37e100385 ("ntfs3: Fix integer overflow in run_unpack()"). Found by fuzzing with a source-patched harness (LibAFL + QEMU).