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/tools/Makefile b/tools/Makefile
index 1f9144f..879c3fd 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -5,7 +5,7 @@
 
 # Enable all the config-independent tools
 ifneq ($(HOST_TOOLS_ALL),)
-CONFIG_KIRKWOOD = y
+CONFIG_ARCH_KIRKWOOD = y
 CONFIG_LCD_LOGO = y
 CONFIG_CMD_LOADS = y
 CONFIG_CMD_NET = y
@@ -199,7 +199,7 @@
 
 HOSTCFLAGS_ubsha1.o := -pedantic
 
-hostprogs-$(CONFIG_KIRKWOOD) += kwboot
+hostprogs-$(CONFIG_ARCH_KIRKWOOD) += kwboot
 hostprogs-$(CONFIG_ARCH_MVEBU) += kwboot
 hostprogs-y += proftool
 hostprogs-$(CONFIG_STATIC_RELA) += relocate-rela