Change in coreboot[master]: Makefile.inc: Generate master header and pointer as C structs

[Arthur Heymans (Code Review)]

Attention is currently required from: Martin Roth, Julius Werner, Arthur Heymans, Yu-Ping Wu.
Arthur Heymans has uploaded a new patch set (#9) to the change originally created by Arthur Heymans. ( https://review.coreboot.org/c/coreboot/+/59132 )

Change subject: Makefile.inc: Generate master header and pointer as C structs
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Makefile.inc: Generate master header and pointer as C structs

The makefiles don't like cbfs file names with spaces in them so update
the file name with '_' instead of spaces. To keep the master header at
the top of cbfs, add a placeholder.

This removes the need to handle the cbfs master header in cbfstool.
This functionality will be dropped in a later CL.

On x86 reserve some space in the linker script to add the pointer.
On non-x86 generate a pointer inside a C struct file.

As a bonus this would actually fix the master header pointer mechanism
on Intel/APL as only the bootblock inside IFWI gets memory mapped.

Change-Id: I3ba01be7da1f09a8cac287751497c18cda97d293
Signed-off-by: Arthur Heymans 
---
M Makefile.inc
M src/arch/x86/bootblock.ld
M src/lib/Makefile.inc
A src/lib/cbfs_master_header.c
A src/lib/master_header_pointer.c
M src/security/vboot/Makefile.inc
6 files changed, 65 insertions(+), 13 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/32/59132/9