[PATCH -next] spi: spi-summary.rst: fix underline length

[Randy Dunlap]

The change to use "target" requires an underline to be extended by
one more character to fix a documentation build warning:

  Documentation/spi/spi-summary.rst:274: WARNING: Title underline too short.
  Declare target Devices
  ^^^^^^^^^^^^^^^^^^^^^

Fixes: hash ("spi: Update the "master/slave" terminology in documentation")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Dhruva Gole <d-gole@xxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: linux-spi@xxxxxxxxxxxxxxx
---
 Documentation/spi/spi-summary.rst |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -- a/Documentation/spi/spi-summary.rst b/Documentation/spi/spi-summary.rst
--- a/Documentation/spi/spi-summary.rst
+++ b/Documentation/spi/spi-summary.rst
@@ -271,7 +271,7 @@ an external clock, where another derives
 settings of some master clock.
 
 Declare target Devices
-^^^^^^^^^^^^^^^^^^^^^
+^^^^^^^^^^^^^^^^^^^^^^
 
 The second kind of information is a list of what SPI target devices exist
 on the target board, often with some board-specific data needed for the