sh: return_address: Add missing #include <asm/ftrace.h>

arch/sh/kernel/return_address.c:49:7: warning: no previous prototype for ‘return_address’ [-Wmissing-prototypes]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/45685f62c9132aca5dc3c028471218393b51f34c.1709326528.git.geert+renesas@glider.beSigned-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>

arch/sh/kernel/return_address.c

@@ -7,7 +7,9 @@
  */
 #include <linux/kernel.h>
 #include <linux/module.h>
+
 #include <asm/dwarf.h>
+#include <asm/ftrace.h>
 
 #ifdef CONFIG_DWARF_UNWINDER