ARM: imx: add missing include

imx25_pm_init() is declared in common.h but this is not included
before its definition:

arch/arm/mach-imx/pm-imx25.c:31:13: error: no previous prototype for 'imx25_pm_init'

Link: https://lore.kernel.org/r/20230516153109.514251-5-arnd@kernel.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-imx/pm-imx25.c

@@ -6,6 +6,7 @@
 #include <linux/kernel.h>
 #include <linux/suspend.h>
 #include <linux/io.h>
+#include "common.h"
 
 static int imx25_suspend_enter(suspend_state_t state)
 {