mfd: palmas: shift the palmas_sleep_requestor_info structure definition to the header file

shift the palmas_sleep_requestor_info structure definition to the header file.

Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>