Megaflash CRC check fix for attic-less boards; a minor fix and an addition for the Wukong board

[0xa000]

This pull request contains:

• A fix for the CRC check in megaflash for all boards without attic RAM.
• A fix for the generated Vivado project file for the Wukong board to include the correct shadow ram file.
• Support for using the second user button on the Wukong board as an alternative Restore key.
• Remove file static (internal) function from header file.

[lydon42]

I am not sure why the CRC logic needs to be changed here. I thought it already does check CRC on boards without attic... Need to understand the changes still, on the first look it does confuse me :)

[0xa000]

It's been a while... I think the CRC fix for no-attic mainly consists of testing for the right status code, as mentioned in the DM below:

... for no attic, megaflash sets mfhf_core_file_state to MFHF_LC_FROMDISK if the CRC check passed, but then on the next lines (416,417) it checks for MFHF_LC_ATTICOK.

Then I found I could simplify the logic around that test such that it works for both the attic and no-attic case. For the attic case, it should be functionally equivalent to the code as it existed before this commit.