ipq806x: introduce ipq8064 SoC v2 dtsi

According to QCA internal numbering there are 3 versions of
ipq8064/5 SoC:
ipq8064 v1.0 - probably ipq8064 evaluation boards only
ipq8064 v2.0 - probably ipq8064 mass market boards only
ipq8064 v3.0 - aka ipq8065, boards based on ipq8065.

Each next revision includes configuration differences from
previous revision and adds something new.

Signed-off-by: Pavel Kubelun <be.dissent@gmail.com>
[slh: rebase for kernel v4.14 as well]
Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>