[media] V4L2 spec: fix the description of V4L2_FBUF_CAP_SRC_CHROMAKEY

V4L2_FBUF_CAP_SRC_CHROMAKEY is the opposite of V4L2_FBUF_CAP_CHROMAKEY, but
according to the documentation it was the same. The terms 'video' and
'framebuffer' were accidentally swapped in the text.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
CC: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/media/v4l/vidioc-g-fbuf.xml

@@ -340,8 +340,8 @@ blending makes no sense for destructive overlays.</entry>
 	  <row>
 	    <entry><constant>V4L2_FBUF_CAP_SRC_CHROMAKEY</constant></entry>
 	    <entry>0x0080</entry>
-	    <entry>The device supports Source Chroma-keying. Framebuffer pixels
-with the chroma-key colors are replaced by video pixels, which is exactly opposite of
+	    <entry>The device supports Source Chroma-keying. Video pixels
+with the chroma-key colors are replaced by framebuffer pixels, which is exactly opposite of
 <constant>V4L2_FBUF_CAP_CHROMAKEY</constant></entry>
 	  </row>
 	</tbody>