aspeed/wdt: Check correct register for clock source

When WDT_RESTART is written, the data is not the contents
of the WDT_CTRL register. Hence ensure we are looking at
WDT_CTRL to check if bit WDT_CTRL_1MHZ_CLK is set or not.

Signed-off-by: Amithash Prasad <amithash@fb.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 20190925143248.10000-2-clg@kaod.org
[clg: improved Suject prefix ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/watchdog/wdt_aspeed.c

@@ -140,7 +140,7 @@ static void aspeed_wdt_write(void *opaque, hwaddr offset, uint64_t data,
     case WDT_RESTART:
         if ((data & 0xFFFF) == WDT_RESTART_MAGIC) {
             s->regs[WDT_STATUS] = s->regs[WDT_RELOAD_VALUE];
-            aspeed_wdt_reload(s, !(data & WDT_CTRL_1MHZ_CLK));
+            aspeed_wdt_reload(s, !(s->regs[WDT_CTRL] & WDT_CTRL_1MHZ_CLK));
         }
         break;
     case WDT_CTRL: