MAINTAINERS: Add missing file include/linux/delay.h

include/linux/delay.h is not covered by MAINTAINERS file. Add it to the
"HIGH-RESOLUTION TIMERS, TIMER WHEEL, CLOCKEVENTS" section.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241014-devel-anna-maria-b4-timers-flseep-v3-1-dc8b907cb62f@linutronix.de