With CONFIG_I2C=m and CONFIG_INTEL_CHT_INT33FE=y we see the following link
errors:

drivers/built-in.o: In function 'cht_int33fe_remove':
intel_cht_int33fe.c:(.text+0x391f6e): undefined reference to 'i2c_unregister_device'
intel_cht_int33fe.c:(.text+0x391f76): undefined reference to 'i2c_unregister_device'
intel_cht_int33fe.c:(.text+0x391f7d): undefined reference to 'i2c_unregister_device'
drivers/built-in.o: In function 'cht_int33fe_probe':
intel_cht_int33fe.c:(.text+0x392147): undefined reference to 'i2c_acpi_new_device'
intel_cht_int33fe.c:(.text+0x392185): undefined reference to 'i2c_acpi_new_device'
intel_cht_int33fe.c:(.text+0x3921bd): undefined reference to 'i2c_acpi_new_device'
intel_cht_int33fe.c:(.text+0x3921d9): undefined reference to 'i2c_unregister_device'
intel_cht_int33fe.c:(.text+0x3921e8): undefined reference to 'i2c_unregister_device'
drivers/built-in.o: In function 'cht_int33fe_driver_init':
intel_cht_int33fe.c:(.init.text+0x2386d): undefined reference to 'i2c_register_driver'
drivers/built-in.o: In function 'cht_int33fe_driver_exit':
intel_cht_int33fe.c:(.exit.text+0x206e): undefined reference to 'i2c_del_driver'

Fix this by adding a kconfig dependency on the I2C subsystem.

Fixes: 1cd706df ("platform/x86: Add Intel Cherry Trail ACPI INT33FE device driver")
Signed-off-by: Tobias Regnery <tobias.regnery@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>