ARM: 8161/1: footbridge: select machine dir based on ARCH_FOOTBRIDGE

Syntactically FOOTBRIDGE and ARCH_FOOTBRIDGE are identical (the former
is defined in an if ARCH_FOOTBRIDGE block and the latter selects the
former).

Sematically FOOTBRIDGE means "we have a DC21285 (aka footbridge) device
in the system" and ARCH_FOOTBRIDGE is the support for boards with a
footbridge device, so ARCH_FOOTBRIDGE is the better symbol here.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Makefile

@@ -157,6 +157,7 @@ machine-$(CONFIG_ARCH_EBSA110)		+= ebsa110
 machine-$(CONFIG_ARCH_EFM32)		+= efm32
 machine-$(CONFIG_ARCH_EP93XX)		+= ep93xx
 machine-$(CONFIG_ARCH_EXYNOS)		+= exynos
+machine-$(CONFIG_ARCH_FOOTBRIDGE)	+= footbridge
 machine-$(CONFIG_ARCH_GEMINI)		+= gemini
 machine-$(CONFIG_ARCH_HIGHBANK)		+= highbank
 machine-$(CONFIG_ARCH_HISI)		+= hisi
@@ -205,7 +206,6 @@ machine-$(CONFIG_ARCH_VEXPRESS)		+= vexpress
 machine-$(CONFIG_ARCH_VT8500)		+= vt8500
 machine-$(CONFIG_ARCH_W90X900)		+= w90x900
 machine-$(CONFIG_ARCH_ZYNQ)		+= zynq
-machine-$(CONFIG_FOOTBRIDGE)		+= footbridge
 machine-$(CONFIG_PLAT_SPEAR)		+= spear
 
 # Platform directory name.  This list is sorted alphanumerically