target: Use kmalloc_array() in compare_and_write_callback()

* A multiplication for the size determination of a memory allocation
indicated that an array data structure should be processed.
Thus use the corresponding function "kmalloc_array".

This issue was detected by using the Coccinelle software.

* Replace the specification of a data structure by a pointer dereference
to make the corresponding size determination a bit safer according to
the Linux coding style convention.

Signed-off-by: Markus Elfring <[e-mail]>
Signed-off-by: Nicholas Bellinger <[e-mail]>

drivers/target/target_core_sbc.c

···
 		goto out;
 	}
 
-	write_sg = kmalloc(sizeof(struct scatterlist) * cmd->t_data_nents,
-			   GFP_KERNEL);
+	write_sg = kmalloc_array(cmd->t_data_nents, sizeof(*write_sg),
+				 GFP_KERNEL);
 	if (!write_sg) {
 		pr_err("Unable to allocate compare_and_write sg\n");
 		ret = TCM_OUT_OF_RESOURCES;