drivers: renesas: watchdog: Move to common

Move watch driver code to common directory, so that the same
code can be re-used by both R-Car Gen3 and RZ/G2 platforms.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Change-Id: I235f2cde325a0feeadbfc4b7ee02e8b1186f7ea1
3 files changed