x86: Tidy up coreboot header usage

There is no need to explicitly write 'arch-coreboot' when including headers,
as when the arch directory points to coreboot the correct files will be
used.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/coreboot/coreboot.c

@@ -16,8 +16,8 @@
 #include <asm/cpu.h>
 #include <asm/io.h>
 #include <asm/post.h>
-#include <asm/arch-coreboot/tables.h>
-#include <asm/arch-coreboot/sysinfo.h>
+#include <asm/arch/tables.h>
+#include <asm/arch/sysinfo.h>
 #include <asm/arch/timestamp.h>
 
 DECLARE_GLOBAL_DATA_PTR;

arch/x86/cpu/coreboot/ipchecksum.c

@@ -30,7 +30,7 @@
  */
 
 #include <compiler.h>
-#include <asm/arch-coreboot/ipchecksum.h>
+#include <asm/arch/ipchecksum.h>
 
 unsigned short ipchksum(const void *vptr, unsigned long nbytes)
 {

arch/x86/cpu/coreboot/tables.c

@@ -8,9 +8,9 @@
  */
 
 #include <common.h>
-#include <asm/arch-coreboot/ipchecksum.h>
-#include <asm/arch-coreboot/sysinfo.h>
-#include <asm/arch-coreboot/tables.h>
+#include <asm/arch/ipchecksum.h>
+#include <asm/arch/sysinfo.h>
+#include <asm/arch/tables.h>
 
 /*
  * This needs to be in the .data section so that it's copied over during