media: Documentation: userspace-api/media: v4l/vidioc-g-output: drop doubled word

Drop the doubled word "standard.".

Signed-off-by: Randy Dunlap <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: [e-mail]
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

Documentation/userspace-api/media/v4l/vidioc-g-output.rst

···
 output in an integer and call the :ref:`VIDIOC_S_OUTPUT <VIDIOC_G_OUTPUT>` ioctl with a
 pointer to this integer. Side effects are possible. For example outputs
 may support different video standards, so the driver may implicitly
-switch the current standard. standard. Because of these possible side
+switch the current standard. Because of these possible side
 effects applications must select an output before querying or
 negotiating any other parameters.