cramfs file size limit

cramfs default maximum file size is 16M (16777215)
if file size > 16M, you'll get this message when mkcramfs
warning: file sizes truncated to 16MB (minus 1 byte).

it's possible to make limit larger!

modify to value CRAMFS_SIZE_WIDTH in kernel source
include/linux/cramfs_fs.h
(default #define CRAMFS_SIZE_WIDTH 24)

after I tested, maximum value is 28, in other word,
file size limit 268435455 (256MB)

don't forget to modify mkcramfs, get cramfs tools and
change the value as above (modify /usr/include/linux/cramfs_fs.h and rebuid mkcramfs), use modified mkcramfs to make cram files.

note. CRAMFS_SIZE_WIDTH in kernel and mkcramfs must be the same,
or cramfs will not work.