pkg/tinycrypt: update commit hash after upstream rewrote history

Upstream rewrote history in master which changed our reference commit from

    https://github.com/01org/tinycrypt/commit/3ea1a609e7aff9f2d8d13803e1076b7a8e551804

to

    https://github.com/01org/tinycrypt/commit/6a22712bebbf2fc60d9fc6192dddefd5ad1933e3

Diff can be verified to be empty with:

    https://github.com/01org/tinycrypt/compare/6a22712bebbf2fc60d9fc6192dddefd5ad1933e3...3ea1a609e7aff9f2d8d13803e1076b7a8e551804