imx: imx7d: add imx-common cpu support for imx7d

Add imx-common cpu support for imx7d SoC
- Update reset_cause for imx7d
- Enable watchdog driver built for imx7d

Signed-off-by: Adrian Alonso <aalonso@freescale.com>
Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 482a4bd..9e9cb55 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -7,7 +7,7 @@
 
 obj-$(CONFIG_AT91SAM9_WATCHDOG) += at91sam9_wdt.o
 obj-$(CONFIG_FTWDT010_WATCHDOG) += ftwdt010_wdt.o
-ifneq (,$(filter $(SOC), mx31 mx35 mx5 mx6 vf610 ls102xa))
+ifneq (,$(filter $(SOC), mx31 mx35 mx5 mx6 mx7 vf610 ls102xa))
 obj-y += imx_watchdog.o
 endif
 obj-$(CONFIG_S5P)               += s5p_wdt.o