omap: Use 32KiHZ timer by default

Use 32KiHZ timer by default as this is available on all omaps
except 15xx based systems.

Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
index 78b49a6..3e2e7a8 100644
--- a/arch/arm/plat-omap/Kconfig
+++ b/arch/arm/plat-omap/Kconfig
@@ -120,7 +120,7 @@
 
 choice
 	prompt "System timer"
-	default OMAP_MPU_TIMER
+	default OMAP_32K_TIMER if !ARCH_OMAP15XX
 
 config OMAP_MPU_TIMER
 	bool "Use mpu timer"