[media] pixfmt-meta-vsp1-hgo.rst: remove spurious '-'

Remove spurious '-' in the VSP1 hgo table.

This resulted in a weird dot character that also caused
the row to be double-height.

We used to have it on other tables, but we got rid of them
on changeset 8ed29e30 ("[media] subdev-formats.rst: remove
spurious '-'").

Fixes: 14d66538 ("[media] v4l: Define a pixel format for the R-Car VSP1 1-D histogram engine")
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>