NFC: pn544: i2c: Add firmware download implementation for pn544

The pn544 can enter a firmware update mode where firmware blobs can be
pushed through the i2c line and flashed on the target.
A special command allows to verify that blobs are correctly flashed and
this is what we do for every downloaded firmware blob.

Signed-off-by: Eric Lapuyade <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>