regulator: max1586 - fix a memory leak in max1586_pmic_remove()

In max1586_pmic_probe(), we allocate memory for max1586.
In max1586_pmic_remove(), current implementation only free rdev
which is a member of struct max1586_data.
Thus, there is a small memory leak when we unload the module.

This patch fixes the memory leak by passing max1586 to i2c clientdata,
and properly kfree(max1586) in max1586_pmic_remove().

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>