watchdog: Let XILINX_WATCHDOG and TEGRA_WATCHDOG depend on HAS_IOMEM

They need HAS_IOMEM, so let them depend on it, the related error (with
allmodconfig under um):

    MODPOST 1205 modules
  ERROR: "devm_ioremap_resource" [drivers/watchdog/tegra_wdt.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/watchdog/of_xilinx_wdt.ko] undefined!
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

@@ -132,6 +132,7 @@ config WM8350_WATCHDOG
 
 config XILINX_WATCHDOG
 	tristate "Xilinx Watchdog timer"
+	depends on HAS_IOMEM
 	select WATCHDOG_CORE
 	help
 	  Watchdog driver for the xps_timebase_wdt ip core.
@@ -472,7 +473,7 @@ config SIRFSOC_WATCHDOG
 
 config TEGRA_WATCHDOG
 	tristate "Tegra watchdog"
-	depends on ARCH_TEGRA || COMPILE_TEST
+	depends on (ARCH_TEGRA || COMPILE_TEST) && HAS_IOMEM
 	select WATCHDOG_CORE
 	help
 	  Say Y here to include support for the watchdog timer