[WATCHDOG] Fix build with CONFIG_ITCO_VENDOR_SUPPORT=n

The problem is that iTCO_vendor_support.ko is still being built while
iTCO_vendor.h claims that its functions do not exist. The following
Makefile update fixes that. It causes iTCO_vendor_support.ko to no
longer be built if CONFIG_ITCO_VENDOR_SUPPORT=n.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Makefile

@@ -66,7 +66,10 @@ obj-$(CONFIG_IB700_WDT) += ib700wdt.o
 obj-$(CONFIG_IBMASR) += ibmasr.o
 obj-$(CONFIG_WAFER_WDT) += wafer5823wdt.o
 obj-$(CONFIG_I6300ESB_WDT) += i6300esb.o
-obj-$(CONFIG_ITCO_WDT) += iTCO_wdt.o iTCO_vendor_support.o
+obj-$(CONFIG_ITCO_WDT) += iTCO_wdt.o
+ifeq ($(CONFIG_ITCO_VENDOR_SUPPORT),y)
+obj-$(CONFIG_ITCO_WDT) += iTCO_vendor_support.o
+endif
 obj-$(CONFIG_IT8712F_WDT) += it8712f_wdt.o
 obj-$(CONFIG_HP_WATCHDOG) += hpwdt.o
 obj-$(CONFIG_SC1200_WDT) += sc1200wdt.o