cbfstool: Change FMD annotation to flags

The idea of "annotation" for firmware sections was pretty flexible, but
in future we will want multiple attributes applied to same area. For
example, indicate the section must be preserved when updating firmware
so serial number or MAC address can be preserved.

The solution here is to extend annotation so it can take multiple
identifiers (flags) in a row. For example, to declare a 64KB COREBOOT
section as CBFS using annotation:

 COREBOOT(CBFS)@0x0 64k

If there's a new flag "PRESERVE" indicating the section must be
preserved before update, we can declare it following CBFS flag:

 COREBOOT(CBFS PRESERVE)@0x0 64k

The flags are directly parsed in fmd_parser, and stored in an union
flashmap_flags. Output modules can choose to ignore or process the
flags.

Currently the only supported flag is "CBFS" (for backward compatible
with annotation). There will be more new flags in follow up patches.

BUG=chromium:936768
TEST=make; boots on x86 "google/eve" and arm "google/kukui" devices

Change-Id: Ie2d99f570e6faff6ed3a4344d6af7526a4515fae
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31706
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

util/cbfstool/fmd_scanner.l

@@ -24,13 +24,16 @@ int copy_string(const char *src);
 %}
 
 %option noyywrap
+%s FLAGS
 
 MULTIPLIER [KMG]
 
 %%
-
 [[:space:]]+                /* Eat whitespace. */
 #.*$                        /* Eat comments. */
+\(                          BEGIN(FLAGS); return *yytext;
+<FLAGS>\)                   BEGIN(INITIAL); return *yytext;
+<FLAGS>CBFS                 return FLAG_CBFS;
 0{MULTIPLIER}?              |
 [1-9][0-9]*{MULTIPLIER}?    return parse_integer(yytext, 10);
 0[0-9]+{MULTIPLIER}?        return OCTAL;