This change implements a driver for the two watchdog timers on the BL808, and enables it as part of the timer config. The driver is based on the GP timer driver.
This PR adds support for PINE64 Ox64 64-bit RISC-V SBC, based on Bouffalo Lab BL808 SoC (T-Head C906 Core). Most of the code is derived from NuttX for Star64 JH7110. The source files are explained in the articles here: https://github.com/lupyuen/nuttx-ox64
### Modified Files
`boards/Kconfig`: Added Ox64 board
### New Files in boards/risc-v/bl808/ox64
`src/bl808_appinit.c`: Startup Code
`include/board.h`: Ox64 Definitions
`include/board_memorymap.h`: Memory Map
`src/etc/init.d/rc.sysinit`, `rcS`: Startup Script
`src/.gitignore`: Ignore the tmp filesystem
`scripts/ld.script`: Linker Script
`scripts/Make.defs`: Ox64 Makefile
`src/Makefile`: Ox64 Makefile
`Kconfig`: Ox64 Config
`configs/nsh/defconfig`: Build Config for `ox64:nsh`
### Updated Documentation
`platforms/risc-v/bl808/index.rst`: New page for Bouffalo Lab BL808 SoC
`platforms/risc-v/bl808/boards/ox64/index.rst`: Building and booting NuttX for Ox64
`platforms/risc-v/jh7110/boards/star64/index.rst`: Fix typo