iommu/intel: Fix out-of-bounds memset in dmar_latency_disable()

iommu/intel: Fix out-of-bounds memset in dmar_latency_disable()

dmar_latency_disable() intends to zero out only the single
latency_statistic entry for the given type, but the memset size was
computed as sizeof(*lstat) * DMAR_LATENCY_NUM, which clears the entire
array starting from &lstat[type].

When type > 0, this writes beyond the end of the allocated array,
corrupting adjacent memory.

Fix by using sizeof(*lstat) to clear only the target entry.

Fixes: 55ee5e67a59a ("iommu/vt-d: Add common code for dmar latency performance monitors")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Will Deacon <will@kernel.org>