ACPI: move declaration acpi_early_init() to acpi.h

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/init/main.c b/init/main.c
index d721dad..f1b9f0f 100644
--- a/init/main.c
+++ b/init/main.c
@@ -24,6 +24,7 @@
 #include <linux/smp_lock.h>
 #include <linux/initrd.h>
 #include <linux/bootmem.h>
+#include <linux/acpi.h>
 #include <linux/tty.h>
 #include <linux/gfp.h>
 #include <linux/percpu.h>
@@ -86,11 +87,6 @@
 extern void prio_tree_init(void);
 extern void radix_tree_init(void);
 extern void free_initmem(void);
-#ifdef	CONFIG_ACPI
-extern void acpi_early_init(void);
-#else
-static inline void acpi_early_init(void) { }
-#endif
 #ifndef CONFIG_DEBUG_RODATA
 static inline void mark_rodata_ro(void) { }
 #endif