regulator: palmas: Rename reg_info to palmas_reg_info

reg_info is a generic term which might cause conflict at a later point
in time. To prevent such a thing from occuring in future, rename to
palmas_reg_info.

Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Tested-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Mark Brown <broonie@linaro.org>