mfd: Move tps65217 regulator plat data handling to regulator

Regulator platform data handling was mistakenly added to MFD
driver. So we will see build errors if we compile MFD drivers
without CONFIG_REGULATOR. This patch moves regulator platform
data handling from TPS65217 MFD driver to regulator driver.

This makes MFD driver independent of REGULATOR framework so
build error is fixed if CONFIG_REGULATOR is not set.

drivers/built-in.o: In function `tps65217_probe':
tps65217.c:(.devinit.text+0x13e37): undefined reference
to `of_regulator_match'

This patch also fix allocation size of tps65217 platform data.
Current implementation allocates a struct tps65217_board for each
regulator specified in the device tree. But the structure itself
provides array of regulators so one instance of it is sufficient.

Signed-off-by: AnilKumar Ch <anilkumar@ti.com>