ARM: plat-versatile: Make PLAT_VERSATILE_LEDS depend on LEDS_CLASS=y

config PLAT_VERSATILE_LEDS needs LEDS_CLASS=y, otherwise I got below build error when CONFIG_LEDS_CLASS=m.

LD init/built-in.o
arch/arm/plat-versatile/built-in.o: In function `versatile_leds_init':
sched-clock.c:(.init.text+0x190): undefined reference to `led_classdev_register'
make: *** [vmlinux] Error 1

---
 arch/arm/plat-versatile/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 81ee7cc..62ffdc7 100644
@@ -13,7 +13,7 @@ config PLAT_VERSATILE_FPGA_IRQ_NR
        depends on PLAT_VERSATILE_FPGA_IRQ
 
 config PLAT_VERSATILE_LEDS
-	def_bool y if LEDS_CLASS
+	def_bool y if LEDS_CLASS=y
 	depends on ARCH_REALVIEW || ARCH_VERSATILE
 
 config PLAT_VERSATILE_SCHED_CLOCK

1.7.9.5