Input: tsc2007 - move header file out of I2C realm

include/linux/i2c is not for client devices. Move the header file to a
more appropriate location.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>