omap2/3: dmtimer: Enable autoidle

This saves some power. OMAP4 version should check for GPT module ID, as
autoidle is only supported on a subset of these.
Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/plat-omap/dmtimer.c

@@ -342,6 +342,10 @@ static void omap_dm_timer_reset(struct omap_dm_timer *timer)
 	l |= 0x02 << 3;  /* Set to smart-idle mode */
 	l |= 0x2 << 8;   /* Set clock activity to perserve f-clock on idle */
 
+	/* Enable autoidle on OMAP2 / OMAP3 */
+	if (cpu_is_omap24xx() || cpu_is_omap34xx())
+		l |= 0x1 << 0;
+
 	/*
 	 * Enable wake-up on OMAP2 CPUs.
 	 */