ARM: dts: configure regulators for Gumstix Pepper

Boot process is halting in midway because some of the necessary voltage
regulators are deemed unused and subsequently powered off, leading to
a completely unresponsive system.

Most of the device nodes had correct voltage regulator attachments.
Yet these nodes had to set stricter enforcement on them through
'regulator-boot-on' and 'regulator-always-on' to function correctly.

The consumers of the regulators this commit affect are the followings:

	DCDC1: vdd_1v8 system supply, USB-PHY, and ADC
	DCDC2: Core domain
	DCDC3: MPU core domain
	 LDO1: RTC
	 LDO2: 3v3 IO domain
	 LDO3: USB-PHY; not a boot-time requirement
	 LDO4: LCD [16:23]

All but LDO3 need to be always-on for the system to be functional.

Additionally regulator-name properties have been added for the kernel to
display the name from the schematic. This will improve diagnostics.

Signed-off-by: Adam YH Lee <adam.yh.lee@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>