Omapconf vayu cpu detect

Implement DRA7xx cpu detection on vayu.

For people new to DRA7xx:
	DRA7xx belongs to OMAP5 technology processor family called Jacinto6 set
	of processors. Even though this uses OMAP5 technology, there is
	significant differences in register and module set available in the
	processor.
	Further information about DRA family of processors can be found here:
	http://www.ti.com/omap-jac6-pr-pf

We start the support with just the detection of CPU information here.

a.)Add new directory "dra7" @ arch/arm/mach-omap/dra7
	and two files, cpuinfo_dra7xx.c & cpuinfo_dra7xx.h,
	which contains the functions to get dra7's max speed
	and processor core number.

b.)Things still need to be fixed in subsequent patches:
These can be found by Searching 'FIXME:'
	1. DRA silicom type detection need to be updated
     	   when ID data is available.
	2. All pmic & audio chips detection.
	3. opp, module, voltage domain, power domain, and clock
	   domain deinitialization functions.