sh: Remove sci_ick clock alias

The sh-sci driver falls back to the peripheral clock if the sci_ick
clock doesn't exist. There's thus no need to create an alias for the
peripheral clock named sci_ick.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>