ARM: dts: add Netronix E70K02 board common file

The Netronix board E70K02 can be found some several Ebook-Readers,
at least the Kobo Libra H2O and the Tolino Vision 5. The board
is equipped with different SoCs requiring different pinmuxes.

    For now the following peripherals are included:
    - LED
    - Power Key
    - Cover (gpio via hall sensor)
    - RC5T619 PMIC
    - Backlight via lm3630a
    - Wifi sdio chip detection (mmc-powerseq and stuff)

    It is based on vendor kernel but heavily reworked due to many
    changed bindings.

Known limitations: cold colored backlight does not work due to
incompatible hard coded overvoltage setting in the driver.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>