[PATCH V2] drm/radeon: Include swiotlb.h if SWIOTLB configured.

[Huacai Chen <chenhc@lemote.com>]

When SWIOTLB is configured, if without this patch kernel compilation
fails with such error messages:

drivers/gpu/drm/radeon/radeon_ttm.c: In function 'radeon_ttm_tt_populate':
drivers/gpu/drm/radeon/radeon_ttm.c:606:2: error: implicit declaration of function 'swiotlb_nr_tbl'
drivers/gpu/drm/radeon/radeon_ttm.c:607:3: warning: passing argument 2 of 'ttm_dma_populate' from incompatible pointer type
include/drm/ttm/ttm_page_alloc.h:81:12: note: expected 'struct device *' but argument is of type 'struct device *'
drivers/gpu/drm/radeon/radeon_ttm.c: In function 'radeon_ttm_tt_unpopulate':
drivers/gpu/drm/radeon/radeon_ttm.c:653:3: warning: passing argument 2 of 'ttm_dma_unpopulate' from incompatible pointer type
include/drm/ttm/ttm_page_alloc.h:82:13: note: expected 'struct device *' but argument is of type 'struct device *'

V2:
1, Add compilation error messages;
2, Make the From: address the same as Signed-off-by address.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Hongliang Tao <taohl@lemote.com>
Signed-off-by: Hua Yan <yanh@lemote.com>
Cc: dri-devel@lists.freedesktop.org
---
 drivers/gpu/drm/radeon/radeon_ttm.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 5b71c71..fc3ac22 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -41,6 +41,10 @@
 #include "radeon_reg.h"
 #include "radeon.h"
 
+#ifdef CONFIG_SWIOTLB
+#include <linux/swiotlb.h>
+#endif
+
 #define DRM_FILE_PAGE_OFFSET (0x100000000ULL >> PAGE_SHIFT)
 
 static int radeon_ttm_debugfs_init(struct radeon_device *rdev);
-- 
1.7.7.3