board: engicam: Fix to remove legacy board/icorem6_rqs

board/icorem6_rqs/ is forgot to remove while moving
common board files together in
(sha1: 52aaddd6

)
"i..MX6: engicam: Add imx6q/imx6ul boards for existing boards"

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>