[coreboot] [PATCH] more intelligent cbfs walker

[Patrick Georgi]

Hi,

attached patch makes the CBFS file lookup skip file data instead of brute-
forcing its way through it, looking for magic numbers.
For one, it should speed up file access, esp. with many entries, but it also 
helps against false positives (eg. seabios, which contains the magic number 
for its own CBFS support, which _might_ just be aligned properly)

Signed-off-by: Patrick Georgi