base-files: drop unused preinit_echo function

It isn't used for years since the old 99_10_run_init has been dropped.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
(cherry picked from commit 1e13c6f77f)

package/base-files/files/lib/preinit/10_indicate_preinit

@@ -147,11 +147,6 @@ preinit_net_echo() {
 	}
 }
 
-preinit_echo() {
-	preinit_net_echo $1
-	echo $1
-}
-
 pi_indicate_preinit() {
 	set_state preinit
 }