watchdog: ts4800: add hardware dependency

The Technologic Systems TS-4800 is an i.MX515 board, so its drivers
are useless unless building a SOC_IMX51 kernel, except for build
testing purposes.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Cc: Damien Riegel <damien.riegel@savoirfairelinux.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -468,6 +468,7 @@ config NUC900_WATCHDOG
 config TS4800_WATCHDOG
 	tristate "TS-4800 Watchdog"
 	depends on HAS_IOMEM && OF
+	depends on SOC_IMX51 || COMPILE_TEST
 	select WATCHDOG_CORE
 	select MFD_SYSCON
 	help