iommu: Initialize domain->handler in iommu_domain_alloc()

Since it is not guaranteed that an iommu driver initializes in its
domain_init() function, it must be initialized with NULL to prevent
calling a function in an arbitrary location when iommu fault occurred.

Change-Id: I1001bc6382cfe1e6cf8f311a822380f4151f8391
Signed-off-by: KyongHo Cho <pullip.cho@samsung.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
[stepanm@codeaurora.org: rebased to before the file moved]
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
diff --git a/drivers/base/iommu.c b/drivers/base/iommu.c
index 9d9e4ab..b8333b0 100644
--- a/drivers/base/iommu.c
+++ b/drivers/base/iommu.c
@@ -68,7 +68,7 @@
 	if (!iommu_found())
 		return NULL;
 
-	domain = kmalloc(sizeof(*domain), GFP_KERNEL);
+	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
 	if (!domain)
 		return NULL;