arch/x86/include: Rename bootblock_common to bootblock_romcc.h

This header is only used for the bootblock compiled with ROMCC. As the
follow-on patches introduce a bootblock which does not make use of
ROMCC, rename this header to prevent confusion.

Change-Id: Id29c5bc6928c11cc7cb922fcfac71e5a3dcd113c
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: https://review.coreboot.org/12867
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/arch/x86/bootblock_normal.c

@@ -12,7 +12,7 @@
  */
 
 #include <smp/node.h>
-#include <arch/bootblock_common.h>
+#include <arch/bootblock_romcc.h>
 #include <pc80/mc146818rtc.h>
 #include <halt.h>
 

src/arch/x86/bootblock_simple.c

@@ -12,7 +12,7 @@
  */
 
 #include <smp/node.h>
-#include <arch/bootblock_common.h>
+#include <arch/bootblock_romcc.h>
 #include <halt.h>
 
 static void main(unsigned long bist)