ARM: at91: remove useless config MACH_AT91SAM9_DT

Now that at91sam9 SoCs are only supported through DT, remove
CONFIG_MACH_AT91SAM9_DT and use CONFIG_SOC_AT91SAM9 instead.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/mach-at91/Kconfig

@@ -174,11 +174,6 @@ config SOC_AT91SAM9N12
 # ----------------------------------------------------------
 endif # SOC_SAM_V4_V5
 
-config MACH_AT91SAM9_DT
-	def_bool SOC_AT91SAM9
-
-# ----------------------------------------------------------
-
 comment "AT91 Feature Selections"
 
 config AT91_SLOW_CLOCK

arch/arm/mach-at91/Makefile

@@ -20,7 +20,7 @@ obj-$(CONFIG_SOC_SAMA5D4)	+= sama5d4.o
 
 # AT91SAM board with device-tree
 obj-$(CONFIG_SOC_AT91RM9200) += board-dt-rm9200.o
-obj-$(CONFIG_MACH_AT91SAM9_DT) += board-dt-sam9.o
+obj-$(CONFIG_SOC_AT91SAM9) += board-dt-sam9.o
 
 # SAMA5 board with device-tree
 obj-$(CONFIG_SOC_SAMA5)		+= board-dt-sama5.o