watchdog: rzv2h_wdt: Add missing MODULE_LICENSE tag to fix modpost error

Add the missing `MODULE_LICENSE()` tag to the `rzv2h_wdt` driver, which
resolves the following modpost error when built as a module:

    ERROR: modpost: missing MODULE_LICENSE() in drivers/watchdog/rzv2h_wdt.o

Fixes: f6febd0 ("watchdog: Add Watchdog Timer driver for RZ/V2H(P)")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
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/20240911132031.544479-1-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>

Author: prabhakarlad

drivers/watchdog/rzv2h_wdt.c

@@ -270,3 +270,4 @@ static struct platform_driver rzv2h_wdt_driver = {
 module_platform_driver(rzv2h_wdt_driver);
 MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>");
 MODULE_DESCRIPTION("Renesas RZ/V2H(P) WDT Watchdog Driver");
+MODULE_LICENSE("GPL");