[PATCH -next] soc/qbman: fix implicit header dependency now causing build fails

[Paul Gortmaker <paul.gortmaker@windriver.com>]

In commit 461a6946b1f9 ("iommu: Remove pci.h include from
trace/events/iommu.h") that header shuffle uncovered an implicit
include in this driver, manifesting as:

    CC      drivers/soc/fsl/qbman/qman_portal.o
    drivers/soc/fsl/qbman/qman_portal.c: In function 'qman_portal_probe':
    drivers/soc/fsl/qbman/qman_portal.c:299:2: error: implicit declaration of function 'dma_set_mask'
    drivers/soc/fsl/qbman/qman_portal.c:299:2: error: implicit declaration of function 'DMA_BIT_MASK'
        if (dma_set_mask(dev, DMA_BIT_MASK(40))) {
        ^

on the corenet32_smp_defconfig (and 64 bit respectively.)  The above
commit was singled out via git bisect.

The header it was implictly relying on getting was dma-mapping.h - so
we explicitly add it here.

Fixes: 461a6946b1f9 ("iommu: Remove pci.h include from trace/events/iommu.h")
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Scott Wood <oss@buserror.net>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 drivers/soc/fsl/qbman/qman_portal.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/soc/fsl/qbman/qman_portal.c b/drivers/soc/fsl/qbman/qman_portal.c
index adbaa30d3c5a..4a6a8ae5e0aa 100644
--- a/drivers/soc/fsl/qbman/qman_portal.c
+++ b/drivers/soc/fsl/qbman/qman_portal.c
@@ -30,6 +30,8 @@
 
 #include "qman_priv.h"
 
+#include <linux/dma-mapping.h>
+
 struct qman_portal *qman_dma_portal;
 EXPORT_SYMBOL(qman_dma_portal);
 
-- 
2.11.0