[AVR32] Correct misspelled CONFIG_BLK_DEV_INITRD variable.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
diff --git a/arch/avr32/kernel/setup.c b/arch/avr32/kernel/setup.c
index bf1f016..d08b0bc 100644
--- a/arch/avr32/kernel/setup.c
+++ b/arch/avr32/kernel/setup.c
@@ -313,7 +313,7 @@
 
 static int __init parse_tag_rdimg(struct tag *tag)
 {
-#ifdef CONFIG_INITRD
+#ifdef CONFIG_BLK_DEV_INITRD
 	struct tag_mem_range *mem = &tag->u.mem_range;
 	int ret;