dma-iommu: Fix compilation when !CONFIG_IOMMU_DMA

Inclusion of include/dma-iommu.h when CONFIG_IOMMU_DMA is not selected
results in the following splat:

In file included from drivers/irqchip/irq-gic-v3-mbi.c:20:0:
./include/linux/dma-iommu.h:95:69: error: unknown type name ‘dma_addr_t’
 static inline int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base)
                                                                     ^~~~~~~~~~
./include/linux/dma-iommu.h:108:74: warning: ‘struct list_head’ declared inside parameter list will not be visible outside of this definition or declaration
 static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list)
                                                                          ^~~~~~~~~
scripts/Makefile.build:312: recipe for target 'drivers/irqchip/irq-gic-v3-mbi.o' failed

Fix it by including linux/types.h.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-5-marc.zyngier@arm.com

include/linux/dma-iommu.h

@@ -17,6 +17,7 @@
 #define __DMA_IOMMU_H
 
 #ifdef __KERNEL__
+#include <linux/types.h>
 #include <asm/errno.h>
 
 #ifdef CONFIG_IOMMU_DMA