[ARM] Feroceon: pass proper -mtune argument to gcc

Compilation for the Feroceon core should use -mtune=marvell-f.  This is
available in Code Sourcery's 2008Q3 release at the moment. Otherwise
fall back to -mtune-=xscale.
Signed-off-by: Nicolas Pitre <nico@marvell.com>

arch/arm/Makefile

@@ -76,6 +76,7 @@ tune-$(CONFIG_CPU_SA110)	:=-mtune=strongarm110
 tune-$(CONFIG_CPU_SA1100)	:=-mtune=strongarm1100
 tune-$(CONFIG_CPU_XSCALE)	:=$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
 tune-$(CONFIG_CPU_XSC3)		:=$(call cc-option,-mtune=xscale,-mtune=strongarm110) -Wa,-mcpu=xscale
+tune-$(CONFIG_CPU_FEROCEON)	:=$(call cc-option,-mtune=marvell-f,-mtune=xscale)
 tune-$(CONFIG_CPU_V6)		:=$(call cc-option,-mtune=arm1136j-s,-mtune=strongarm)
 
 ifeq ($(CONFIG_AEABI),y)