staging: greybus: light.c: Remove include linux/version.h

Fixes:
$ make versioncheck | grep staging
./drivers/staging/greybus/light.c: 15 linux/version.h not needed.

Signed-off-by: Darryl T. Agostinelli <dagostinelli@gmail.com>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>