ARM: DRA752: Add ID detect for ES2.0

ES2.0 is a minor variant of ES1.1. ES2.0 is an incremental revision
with various fixes including the following:
	- reset logic fixes
	- few assymetric aging logic fixes
	- MMC clock rate fixes
	- Ethernet speed fixes
	- edma fixes for mcasp

NOTE: even though we use a compatible of dra742 and dra752, the usage in
the Linux kernel is more or less interchangable - we use dra752 more
often in the linux kernel compared to dra742 and 4.2-rc6

Signed-off-by: Vishal Mahaveer <vishalm@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>