[PATCH] dma-buf.rst: repair length of title underline

[Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>]

With commit 72b6ede73623 ("dma-buf.rst: Document why indefinite fences are
a bad idea"), document generation warns:

  Documentation/driver-api/dma-buf.rst:182: \
  WARNING: Title underline too short.

Repair length of title underline to remove warning.

Fixes: 72b6ede73623 ("dma-buf.rst: Document why indefinite fences are a bad idea")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>
---
Daniel, please pick this minor non-urgent fix to your new documentation.

 Documentation/driver-api/dma-buf.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst
index 100bfd227265..13ea0cc0a3fa 100644
--- a/Documentation/driver-api/dma-buf.rst
+++ b/Documentation/driver-api/dma-buf.rst
@@ -179,7 +179,7 @@ DMA Fence uABI/Sync File
    :internal:
 
 Indefinite DMA Fences
-~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~
 
 At various times &dma_fence with an indefinite time until dma_fence_wait()
 finishes have been proposed. Examples include:
-- 
2.17.1