aes: add code to encrypt/decrypt using the aes engine

[DacoTaco]

@GaryOderNichts since it is mostly your code, feel free to review the changes in libogc to support the aes engine through /dev/aes

ill merge it when you accept the changes to your code

[GaryOderNichts]

Thanks for making this into a PR. Left some comments on the code.
Also you should probably convert everything to tabs instead of spaces for consistency with the rest of libogc, I think discord turned it into spaces.

[DacoTaco]

huh, i didn't notice the spaces before.
fixed it, together with your other remarks

[GaryOderNichts]

AES_BLOCK_SIZE is still defined in both files. Can probably be removed from the .c.
Looks good otherwise 👍