mfd: lp87565: Convert to use devm_mfd_add_devices()

This fixes missing mfd_remove_devices() call when unload the module.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>