serial: sh-sci: Drop support for "sci_ick" clock

Since commit 1b463bd51042927e ("ARM: dts: r8a7794: Rename the serial
port clock to fck") in v4.6, all upstream DTS files call the SCIF
functional clock "fck".

Hence the time is ripe to drop backward-compatibility with old DTBs that
use the old "sci_ick" name.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/b4103e44d6ac46b6c1c264e2aeac80b39941fe74.1639663832.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 86731b8..f63b5a6 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -2785,17 +2785,6 @@ static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
 
 		if (IS_ERR(clk) && i == SCI_FCK) {
 			/*
-			 * "fck" used to be called "sci_ick", and we need to
-			 * maintain DT backward compatibility.
-			 */
-			clk = devm_clk_get(dev, "sci_ick");
-			if (PTR_ERR(clk) == -EPROBE_DEFER)
-				return -EPROBE_DEFER;
-
-			if (!IS_ERR(clk))
-				goto found;
-
-			/*
 			 * Not all SH platforms declare a clock lookup entry
 			 * for SCI devices, in which case we need to get the
 			 * global "peripheral_clk" clock.