dts/ls2080a: Update DTSI to add support of SP805 WDT

This patch updates the LS2080a DTSI (DTS Include) file to add
support for eight SP805 Watchdog units which can be used to
reset the eight Cortex-A57 cores available on LS2080A.

Signed-off-by: Bhupesh Sharma <bhupesh.sharma@freescale.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>