watchdog: rzv2h_wdt: Use local `dev` pointer in probe

Update the `rzv2h_wdt_probe()` function to consistently use the local
`dev` pointer, which is already extracted from `&pdev->dev`.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20241213171157.898934-1-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>