watchdog: mpc8xx_wdt: Watchdog driver and macros cleanup

With the generic watchdog driver now implemented, this patch removes
some legacy stuff from the MPC8xx watchdog driver and its Kconfig
integration. CONFIG_MPC8xx_WATCHDOG is completely removed and
hw_watchdog_reset() is made static, as the watchdog will now get
serviced via the DM infrastructure if enabled via CONFIG_WATCHDOG.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
diff --git a/drivers/watchdog/mpc8xx_wdt.c b/drivers/watchdog/mpc8xx_wdt.c
index c24c2a9..675b62d 100644
--- a/drivers/watchdog/mpc8xx_wdt.c
+++ b/drivers/watchdog/mpc8xx_wdt.c
@@ -10,7 +10,7 @@
 #include <asm/cpm_8xx.h>
 #include <asm/io.h>
 
-void hw_watchdog_reset(void)
+static void hw_watchdog_reset(void)
 {
 	immap_t __iomem *immap = (immap_t __iomem *)CONFIG_SYS_IMMR;
 
@@ -18,7 +18,6 @@
 	out_be16(&immap->im_siu_conf.sc_swsr, 0xaa39);	/* write magic2 */
 }
 
-#ifdef CONFIG_WDT_MPC8xx
 static int mpc8xx_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
 {
 	immap_t __iomem *immap = (immap_t __iomem *)CONFIG_SYS_IMMR;
@@ -66,4 +65,3 @@
 	.of_match = mpc8xx_wdt_ids,
 	.ops = &mpc8xx_wdt_ops,
 };
-#endif /* CONFIG_WDT_MPC8xx */