crypto: atmel-i2c - select CONFIG_BITREVERSE

The bitreverse helper is almost always built into the kernel,
but in a rare randconfig build it is possible to hit a case
in which it is a loadable module while the atmel-i2c driver
is built-in:

arm-linux-gnueabi-ld: drivers/crypto/atmel-i2c.o: in function `atmel_i2c_checksum':
atmel-i2c.c:(.text+0xa0): undefined reference to `byte_rev_table'

Add one more 'select' statement to prevent this.

Fixes: 11105693 ("crypto: atmel-ecc - introduce Microchip / Atmel ECC driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>