Print exact addresses to stderr if there are wrong

[keelung-yang]

We got an error after installing our new nand chip.

mtd: bootstream too large

But how large exactly?

and in source code: `static int fill_fcb(struct mtd_data md, FILE fp) { ...

if (boot_stream_size_in_bytes >= max_boot_stream_size_in_bytes) {
    fprintf(stderr, "mtd: bootstream too large\n");
    return -1;

}`

SO please print boot_stream_size_in_bytes and max_boot_stream_size_in_bytes at least, it's very helpful to identify error.

This is just one case, other code should be improved too.

[keelung-yang]

Close it since I've done the job. See

Improve mtd error log #17