watchdog-for-linus-v4.11

Key changes:

- New drivers:
  Cortina Gemini
  ZTE's zx2967 family
  NIC7018
- Convert to use device managed functions:
  ebc-c384_wdt, tegra_wdt, da9063_wdt, da9062_wdt, da9055_wdt, da9052_wdt,
  bcm2835_wdt, mena21_wdt, wm831x_wdt, digicolor_wdt, intel-mid_wdt,
  meson_wdt, sunxi_wdt, aspeed_wdt, coh901327_wdt, iTCO_wdt
- Use watchdog core to install restart handler:
  tangox, dw_wdt, bcm2835_wdt, asm9260_wdt, bcm47xx_wdt
- Convert ts72xx_wdt driver to watchdog core
- Let core handle heartbeat in ep93xx_wdt driver
- Enable COMPILE_TEST where possible
- Various other improvements