crypto: atmel-i2c - rename read function

Make the memory read function name more specific to the read memory zone.
The Atmel SHA204 chips provide config, otp and data zone. The implemented
read function in fact only reads some fields in zone config. The function
renaming allows for a uniform naming scheme when reading from other memory
zones.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>