kconfig: Fix defconfig when one choice menu selects options that another choice menu depends on

The defconfig and Kconfig combination below, which is based on 3.10-rc4
Kconfigs, resulted in several options getting set to "m" instead of "y".

defconfig:
---
CONFIG_MODULES=y
CONFIG_USB_GADGET=y
CONFIG_USB_ZERO=y
---

Kconfig:
---
menuconfig MODULES
	bool "Enable loadable module support"

config CONFIGFS_FS
	tristate "Userspace-driven configuration filesystem"

config OCFS2_FS
        tristate "OCFS2 file system support"
        depends on CONFIGFS_FS
        select CRC32

config USB_LIBCOMPOSITE
	tristate
	select CONFIGFS_FS

choice
	tristate "USB Gadget Drivers"
	default USB_ETH

config USB_ZERO
	tristate "Gadget Zero (DEVELOPMENT)"
	select USB_LIBCOMPOSITE

config USB_ETH
	tristate "Ethernet Gadget (with CDC Ethernet support)"
	select USB_LIBCOMPOSITE

endchoice

config CRC32
        tristate "CRC32/CRC32c functions"
        default y

choice
        prompt "CRC32 implementation"
        depends on CRC32
        default CRC32_SLICEBY8

config CRC32_SLICEBY8
        bool "Slice by 8 bytes"

endchoice

---

Signed-off-by: Arve Hjønnevåg <arve@android.com>