ARM: kirkwood: move SOC sources to mach-kirkwood

Move
arch/arm/cpu/arm926ejs/kirkwood/* -> arch/arm/mach-kirkwood/*

Note:
 Perhaps, can we merge arch/arm/mach-kirkwood and
 arch/arm/mvebu-common into arch/arm/mach-mvebu, like Linux?

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Stefan Roese <sr@denx.de>
Cc: Prafulla Wadaskar <prafulla@marvell.com>
Cc: Luka Perkov <luka.perkov@sartura.hr>
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index e321057..e09de51 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -6,6 +6,8 @@
 # by CONFIG_* macro name.
 machine-$(CONFIG_ARCH_AT91)		+= at91
 machine-$(CONFIG_ARCH_DAVINCI)		+= davinci
+# TODO: rename CONFIG_KIRKWOOD -> CONFIG_ARCH_KIRKWOOD
+machine-$(CONFIG_KIRKWOOD)		+= kirkwood
 # TODO: rename CONFIG_TEGRA -> CONFIG_ARCH_TEGRA
 machine-$(CONFIG_TEGRA)			+= tegra