CHROMIUM: config: Build spidev into the kernel (not a module)

CHROMIUM: config: Build spidev into the kernel (not a module)

A recovery image needs to be able to access SPI in order to reflash
the firmware, but the recovery image doesn't include any modules.
Make spidev part of the kernel to avoid having yet another weird
config difference for the recovery kernel.

BUG=chrome-os-partner:13068
TEST=Manual:
1. Get an official recovery image (that is marked to do a firmware
   flash) that contains this CL plus the modification to
   mod_image_for_recovery.sh that enables it.
2. Boot on snow.
3. After reboot confirm that firmware got updated.
4. Also after reboot look in console-ramoops.  If you see this:
    [ 1157.020235] Chromium OS LSM: init_module locked module=
    "/lib/modules/3.4.0/kernel/drivers/spi/spidev.ko" pid=1574
    cmdline="modprobe spidev"
   ...then that's bad and it means that we loaded the spidev module
   from the target USB key which isn't what we want to do.
TEST=Manual:
1. Hack up recovery image as described in chrome-os-partner:13068.
2. From first shell prompt in hacked recovery image type:
   chroot /usb /usr/sbin/flashrom -r /tmp/foo.bin
3. Confirm that flashrom reports no errors.
4. Type lsmod
5. Confirm that spidev is not listed

Change-Id: Ic156895cb186d04d2c32370d7cf70a3ec4af55bc
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/44311
Reviewed-by: Mike Frysinger <vapier@chromium.org>