ARM: at91: pm: move SAM9X60's PM under its own SoC config flag

Move SAM9X60's PM part under SoC config flag. This allows the building
of SAM9X60 platform withouth depending on CONFIG_SOC_AT91SAM9 flag,
allowing us to select only necessary config flags for SAM9X60.

Signed-off-by: Claudiu Beznea <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexandre Belloni <[e-mail]>

arch/arm/mach-at91/Makefile

···
 # CPU-specific support
 obj-$(CONFIG_SOC_AT91RM9200)	+= at91rm9200.o
 obj-$(CONFIG_SOC_AT91SAM9)	+= at91sam9.o
+obj-$(CONFIG_SOC_SAM9X60)	+= sam9x60.o
 obj-$(CONFIG_SOC_SAMA5)		+= sama5.o
 obj-$(CONFIG_SOC_SAMV7)		+= samv7.o
 

arch/arm/mach-at91/at91sam9.c

···
 	.init_machine	= at91sam9_init,
 	.dt_compat	= at91_dt_board_compat,
 MACHINE_END
-
-static void __init sam9x60_init(void)
-{
-	of_platform_default_populate(NULL, NULL, NULL);
-
-	sam9x60_pm_init();
-}
-
-static const char *const sam9x60_dt_board_compat[] __initconst = {
-	"microchip,sam9x60",
-	NULL
-};
-
-DT_MACHINE_START(sam9x60_dt, "Microchip SAM9X60")
-	/* Maintainer: Microchip */
-	.init_machine	= sam9x60_init,
-	.dt_compat	= sam9x60_dt_board_compat,
-MACHINE_END

arch/arm/mach-at91/pm.c

···
 
 void __init sam9x60_pm_init(void)
 {
-	if (!IS_ENABLED(CONFIG_SOC_AT91SAM9))
+	if (!IS_ENABLED(CONFIG_SOC_SAM9X60))
 		return;
 
 	at91_pm_modes_init();

arch/arm/mach-at91/sam9x60.c

···
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Setup code for SAM9X60.
+ *
+ * Copyright (C) 2019 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Claudiu Beznea <[e-mail]>
+ */
+
+#include <linux/of.h>
+#include <linux/of_platform.h>
+
+#include <asm/mach/arch.h>
+#include <asm/system_misc.h>
+
+#include "generic.h"
+
+static void __init sam9x60_init(void)
+{
+	of_platform_default_populate(NULL, NULL, NULL);
+
+	sam9x60_pm_init();
+}
+
+static const char *const sam9x60_dt_board_compat[] __initconst = {
+	"microchip,sam9x60",
+	NULL
+};
+
+DT_MACHINE_START(sam9x60_dt, "Microchip SAM9X60")
+	/* Maintainer: Microchip */
+	.init_machine	= sam9x60_init,
+	.dt_compat	= sam9x60_dt_board_compat,
+MACHINE_END