x86: add kernel module for sp5100_tco watchdog

This change adds the sp5100_tco driver as a kernel module for the x86
target. Specifically, this can be used by the PCEngines APU2/APU3. The
reason for having this as a kernel module is to allow users to
load/unload it on demand, as the I2C interface on the APU2/APU3 will not
work while this module is loaded. More info can be found on GitHub at
https://github.com/riptidewave93/LEDE-APU2/pull/5#issuecomment-255667736

Signed-off-by: Chris Blake <chrisrblake93@gmail.com>

target/linux/x86/modules.mk

@@ -19,3 +19,18 @@ define KernelPackage/sound-cs5535audio/description
 endef
 
 $(eval $(call KernelPackage,sound-cs5535audio))
+
+define KernelPackage/sp5100_tco
+  SUBMENU:=$(OTHER_MENU)
+  TITLE:=SP5100 Watchdog Support
+  DEPENDS:=@TARGET_x86
+  KCONFIG:=CONFIG_SP5100_TCO
+  FILES:=$(LINUX_DIR)/drivers/watchdog/sp5100_tco.ko
+  AUTOLOAD:=$(call AutoLoad,50,sp5100_tco,1)
+endef
+
+define KernelPackage/sp5100_tco/description
+ Kernel module for the SP5100_TCO hardware watchdog.
+endef
+
+$(eval $(call KernelPackage,sp5100_tco))