rename symbol: CONFIG_KIRKWOOD -> CONFIG_ARCH_KIRKWOOD

Have this symbol follow the pattern of all other such symbols.
This patch also removes a TODO from the code.

Reviewed-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Trevor Woerner <twoerner@gmail.com>
diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 6019ac0..9ced9c0 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -46,7 +46,7 @@
 #include <linux/mbus.h>
 
 #include <asm/arch/soc.h>
-#if defined(CONFIG_KIRKWOOD)
+#if defined(CONFIG_ARCH_KIRKWOOD)
 #define SATAHC_BASE		KW_SATA_BASE
 #else
 #define SATAHC_BASE		MVEBU_AXP_SATA_BASE