Convert ARC boards to device tree

[galak]

The following boards need to get converted:

• arduino_101_sss
• em_starterkit
• panther_ss (no need to do this, will be dropped)
• quark_se_c1000_ss_devboard

[SavinayDharmappa]

@galak @nashif arduino_101_sss dts support is added only for em_starterkit needs to added

[linkmeyer]

I moved the milestone to v1.12 per Manoj's feedback that it will not be fixed until then.

[nashif]

was completed by @galak