ARM: imx: remove dead left-over from i.MX{27,31,35} removal

The commits:

  commit 879c0e5e ("ARM: imx: Remove i.MX27 board files")
  commit c93197b0 ("ARM: imx: Remove i.MX31 board files")
  commit e1324ece ("ARM: imx: Remove i.MX35 board files")

remove the config MACH_MX27_3DS, MACH_MX31_3DS and MACH_MX35_3DS.
Commit a542fc18 ("ARM: imx31: Remove remaining i.MX31 board code")
further removes arch/arm/mach-imx/3ds_debugboard.{c,h}. So, only some
dead left-over in Kconfig and Makefile remains.

Remove this remaining left-over.

This issue was identified with ./scripts/checkkconfigsymbols.py,
which warns on references to the non-existing configs
MACH_MX{27,31,35}_3DS in ./arch/arm/mach-imx/Kconfig.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/mach-imx/Kconfig

@@ -21,18 +21,6 @@ config MXC_TZIC
 config MXC_AVIC
 	bool
 
-config MXC_DEBUG_BOARD
-	bool "Enable MXC debug board(for 3-stack)"
-	depends on MACH_MX27_3DS || MACH_MX31_3DS || MACH_MX35_3DS
-	help
-	  The debug board is an integral part of the MXC 3-stack(PDK)
-	  platforms, it can be attached or removed from the peripheral
-	  board. On debug board, several debug devices(ethernet, UART,
-	  buttons, LEDs and JTAG) are implemented. Between the MCU and
-	  these devices, a CPLD is added as a bridge which performs
-	  data/address de-multiplexing and decode, signal level shift,
-	  interrupt control and various board functions.
-
 config HAVE_IMX_ANATOP
 	bool
 

arch/arm/mach-imx/Makefile

@@ -14,8 +14,6 @@ obj-$(CONFIG_SOC_IMX5) += cpu-imx5.o $(imx5-pm-y)
 obj-$(CONFIG_MXC_TZIC) += tzic.o
 obj-$(CONFIG_MXC_AVIC) += avic.o
 
-obj-$(CONFIG_MXC_DEBUG_BOARD) += 3ds_debugboard.o
-
 ifeq ($(CONFIG_CPU_IDLE),y)
 obj-$(CONFIG_SOC_IMX5) += cpuidle-imx5.o
 obj-$(CONFIG_SOC_IMX6Q) += cpuidle-imx6q.o