watchdog: arm_smc_wdt: add watchdog support

Implement a ARM SMCCC based driver that allow to use
a secure watchdog on the platform.

Signed-off-by: Lionel Debieve <lionel.debieve@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
3 files changed