watchdog: sunxi: fix activation of system reset

Commit f2147de33470 ("watchdog: sunxi: support parameterized compatible
strings") introduced a regression in sunxi_wdt_start(), by which
the system reset function of the watchdog is not enabled upon
starting the watchdog. As a result, the system is not reset when the
watchdog expires. Fix it.

Fixes: f2147de33470 ("watchdog: sunxi: support parameterized compatible strings")
Signed-off-by: Francesco Lavra <[e-mail]>
Acked-by: Maxime Ripard <[e-mail]>
Reviewed-by: Guenter Roeck <[e-mail]>
Signed-off-by: Wim Van Sebroeck <[e-mail]>
Cc: [e-mail]

drivers/watchdog/sunxi_wdt.c

···
 	/* Set system reset function */
 	reg = readl(wdt_base + regs->wdt_cfg);
 	reg &= ~(regs->wdt_reset_mask);
-	reg |= ~(regs->wdt_reset_val);
+	reg |= regs->wdt_reset_val;
 	writel(reg, wdt_base + regs->wdt_cfg);
 
 	/* Enable watchdog */