src/lib: Remove unused <delay.h>

Found using:
diff <(git grep -l '#include <delay.h>' -- src/) <(git grep -l 'get_timer_fsb(\|init_timer(\|udelay(\|mdelay(\|delay(' -- src/) |grep "<"

Change-Id: I6fb603a17534e3a1593cb421c618f8119933292a
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60610
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/lib/dp_aux.c

@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
-#include <delay.h>
 #include <dp_aux.h>
 #include <console/console.h>
 #include <timer.h>