ARM: mach-imx: Kconfig: Remove IMX_HAVE_PLATFORM_IMX2_WDT from SOC_IMX53

SOC_IMX53 is a device-tree only platform, so we don't need
IMX_HAVE_PLATFORM_IMX2_WDT at all because this symbol only provides some code
to help register imx2-wdt platform devices.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/mach-imx/Kconfig

@@ -771,7 +771,6 @@ config	SOC_IMX50
 config	SOC_IMX53
 	bool "i.MX53 support"
 	select HAVE_IMX_SRC
-	select IMX_HAVE_PLATFORM_IMX2_WDT
 	select PINCTRL_IMX53
 	select SOC_IMX5