powerpc: mpc8xx: move watchdog into drivers/watchdog

In preparation of DM watchdog, move basic actions into drivers/watchdog

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index af45cfe..13a7956 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -34,7 +34,7 @@
 	bool "MPC8xx"
 	select BOARD_EARLY_INIT_F
 	imply CMD_REGINFO
-	imply HW_WATCHDOG
+	imply MPC8xx_WATCHDOG
 
 endchoice
 
diff --git a/arch/powerpc/cpu/mpc8xx/Kconfig b/arch/powerpc/cpu/mpc8xx/Kconfig
index f112317..b0e90a0 100644
--- a/arch/powerpc/cpu/mpc8xx/Kconfig
+++ b/arch/powerpc/cpu/mpc8xx/Kconfig
@@ -25,6 +25,10 @@
 
 endchoice
 
+config MPC8xx_WATCHDOG
+	bool "Watchdog"
+	select HW_WATCHDOG
+
 config 8xx_GCLK_FREQ
 	int "CPU GCLK Frequency"
 
diff --git a/arch/powerpc/cpu/mpc8xx/cpu.c b/arch/powerpc/cpu/mpc8xx/cpu.c
index 7608970..d17ad84 100644
--- a/arch/powerpc/cpu/mpc8xx/cpu.c
+++ b/arch/powerpc/cpu/mpc8xx/cpu.c
@@ -270,18 +270,6 @@
 	return oscclk / 16;
 }
 
-/* ------------------------------------------------------------------------- */
-
-#if defined(CONFIG_HW_WATCHDOG)
-void hw_watchdog_reset(void)
-{
-	immap_t __iomem *immr = (immap_t __iomem *)CONFIG_SYS_IMMR;
-
-	out_be16(&immr->im_siu_conf.sc_swsr, 0x556c);	/* write magic1 */
-	out_be16(&immr->im_siu_conf.sc_swsr, 0xaa39);	/* write magic2 */
-}
-#endif /* CONFIG_WATCHDOG */
-
 /*
  * Initializes on-chip ethernet controllers.
  * to override, implement board_eth_init()