common: Move relocate_code() to init.h

This is an init function so move it out of the common header. Avoid using
the typedef so that we don't have to include the global_data header file.

Also tidy up the function style in comments while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/lib/relocate_64.S b/arch/arm/lib/relocate_64.S
index 26d29c5..72e91f2 100644
--- a/arch/arm/lib/relocate_64.S
+++ b/arch/arm/lib/relocate_64.S
@@ -14,7 +14,7 @@
 #include <asm/macro.h>
 
 /*
- * void relocate_code (addr_moni)
+ * void relocate_code(addr_moni)
  *
  * This function relocates the monitor code.
  * x0 holds the destination address.