ARM: imx_v6_v7_defconfig: Enable CONFIG_IMX7ULP_WDT by default

Select CONFIG_IMX7ULP_WDT by default to support i.MX7ULP watchdog.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/configs/imx_v6_v7_defconfig

@@ -236,6 +236,7 @@ CONFIG_DA9062_WATCHDOG=y
 CONFIG_DA9063_WATCHDOG=m
 CONFIG_RN5T618_WATCHDOG=y
 CONFIG_IMX2_WDT=y
+CONFIG_IMX7ULP_WDT=y
 CONFIG_MFD_DA9052_I2C=y
 CONFIG_MFD_DA9062=y
 CONFIG_MFD_DA9063=y