at91: switch to CLKDEV_LOOKUP

we do not change the clock naming convention so does not need to switch
the AVR32 yet

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Patrice Vilchez <patrice.vilchez@atmel.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7275009..5fd0be9 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -294,6 +294,7 @@
 	bool "Atmel AT91"
 	select ARCH_REQUIRE_GPIOLIB
 	select HAVE_CLK
+	select CLKDEV_LOOKUP
 	help
 	  This enables support for systems based on the Atmel AT91RM9200,
 	  AT91SAM9 and AT91CAP9 processors.