AMD IOMMU: add stats counter for free_coherent requests

Impact: see number of free_coherent requests in debugfs

Signed-off-by: Joerg Roedel <[e-mail]>

arch/x86/kernel/amd_iommu.c

···
 DECLARE_STATS_COUNTER(cnt_map_sg);
 DECLARE_STATS_COUNTER(cnt_unmap_sg);
 DECLARE_STATS_COUNTER(cnt_alloc_coherent);
+DECLARE_STATS_COUNTER(cnt_free_coherent);
 
 static struct dentry *stats_dir;
 static struct dentry *de_isolate;
···
 	amd_iommu_stats_add(&cnt_map_sg);
 	amd_iommu_stats_add(&cnt_unmap_sg);
 	amd_iommu_stats_add(&cnt_alloc_coherent);
+	amd_iommu_stats_add(&cnt_free_coherent);
 }
 
 #endif
···
 	struct amd_iommu *iommu;
 	struct protection_domain *domain;
 	u16 devid;
+
+	INC_STATS_COUNTER(cnt_free_coherent);
 
 	if (!check_device(dev))
 		return;