mfd: twl-core: allow enable SR path for TWL4030 family

TWL4030 family of Power Management ICs(PMIC) allow control of PMIC's
VDD1,2 supplies using either I2C1 (regular control I2C path) OR over
I2C_SR (dedicated SR path for communication with dedicated hardware
I2C controllers such as OMAP's Voltage Controller(VC) interface)

However only one path can be active at any given time. Hence, allow
this to be selected using device tree node description.

Signed-off-by: Nishanth Menon <nm@ti.com>
ARM: dts: twl4030_omap3: Link voltage processor to TWL4030

Associate TWl4030 VDD1 for VDD_MPU and VDD2 to VDD_CORE using
corresponding VP path.

Signed-off-by: Nishanth Menon <nm@ti.com>
ARM: dts: twl6030/omap4: Add OMAP voltage path linkage

OMAP4430 and 4460 platforms use TWL6030 to power voltage rails.
However, on 4460, we use twl6030 only for iva and core voltage rails.

Introduce an twl6030_omap4.dtsi to be able to reuse the base definition
for all OMAP4 platforms and the delta change only for panda-es platform
which is based on 4460.

Signed-off-by: Nishanth Menon <nm@ti.com>
ARM: dts: omap4-panda-es: add TPS62361 supply for vdd_mpu

Unlike other OMAP4 platforms including the the "vanilla" PandaBoard,
PandaBoard-ES uses TPS62361 to supply vdd_mpu.

Signed-off-by: Nishanth Menon <nm@ti.com>
ARM: dts: omap4-panda-es: use tps regulator as cpu0 supply

TPS62361 is used for cpufreq regulation. As part of this change
use labels that can be used to reference cpu0 to setup it's supply.

Signed-off-by: Nishanth Menon <nm@ti.com>