watchdog: iTCO: Fix dependencies on I2C

If I2C is built as module, the iTCO watchdog driver must be built as module
as well. I2C_I801 must only be selected if I2C is configured.

This fixes the following build errors, seen if I2C=m and ITCO_WDT=y.

i2c-i801.c:(.text+0x2bf055): undefined reference to `i2c_del_adapter'
i2c-i801.c:(.text+0x2c13e0): undefined reference to `i2c_add_adapter'
i2c-i801.c:(.text+0x2c17bd): undefined reference to `i2c_new_device'

Fixes: 2a7a0e9bf7b3 ("watchdog: iTCO_wdt: Add support for TCO on Intel Sunrisepoint")
Reviewed-by: Matt Fleming <[e-mail]>
Cc: Lee Jones <[e-mail]>
Signed-off-by: Guenter Roeck <[e-mail]>
Signed-off-by: Wim Van Sebroeck <[e-mail]>

drivers/watchdog/Kconfig

···
 	tristate "Intel TCO Timer/Watchdog"
 	depends on (X86 || IA64) && PCI
 	select WATCHDOG_CORE
+	depends on I2C || I2C=n
 	select LPC_ICH if !EXPERT
-	select I2C_I801 if !EXPERT
+	select I2C_I801 if !EXPERT && I2C
 	---help---
 	  Hardware driver for the intel TCO timer based watchdog devices.
 	  These drivers are included in the Intel 82801 I/O Controller