Improvements for the KV info portion of libxenon

[mitchellwaite]

This PR contains a few changes that i've found useful from my own fork of libxenon:

Console info:

• Console serial number is written to the log after the DVD key (based on code from https://github.com/Octal450/libxenon/blob/master/libxenon/drivers/xb360/xb360.c)

Error message improvements

• KV hash failure message is now its own function, reduce code dup
• KV hash failure message actually prints the expected location and size of the KV
• If KV size or offset is zero, a separate error is written (xeBuild has a bug where they aren't set for certain image types, it's useful to know if this is a problem rather than silently not printing the DVD key)

Output will look like the following:

fuseset 09: 0000000000000000
fuseset 10: 0000000000000000
fuseset 11: 0000000000000000

 * CPU key: FF6750B8B5284CF0DC30C85F4CF9931B
 * DVD key: 88FD273A51C3832B731EC74B26E92490
 * Serial: 098721183507