busybox

i2cdump: don't read block data in non-block modes

We currently read data twice in byte mode. Add a check to avoid calling
i2c_smbus_read_i2c_block_data() if we're not in I2C or SMBus block mode.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>