mfd: ti-lmu: Remove support for LM3697

Remove support for the LM3697 from the ti-lmu driver in favor
of a dedicated LED driver.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>