ARM: OMAP2+: AM43x: basic dt support

Describe minimal DT boot machine details for AM43x based SoC's. AM43x
SoC's are ARM Cortex-A9 based with one core. AM43x is similar to
AM335x w.r.t L4 PER/WKUP memory map. AM43x has a sync timer, here that
is being used as clocksource, while 1ms dmtimer as clockevent.

Signed-off-by: Ankur Kishore <a-kishore@ti.com>
Signed-off-by: Afzal Mohammed <afzal@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/timer.c

@@ -582,7 +582,7 @@ OMAP_SYS_32K_TIMER_INIT(2, 1, "timer_32k_ck", "ti,timer-alwon",
 			2, "timer_sys_ck", NULL);
 #endif /* CONFIG_ARCH_OMAP2 */
 
-#ifdef CONFIG_ARCH_OMAP3
+#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM43XX)
 OMAP_SYS_32K_TIMER_INIT(3, 1, "timer_32k_ck", "ti,timer-alwon",
 			2, "timer_sys_ck", NULL);
 OMAP_SYS_32K_TIMER_INIT(3_secure, 12, "secure_32k_fck", "ti,timer-secure",