According to the I2C specification device address 0 is the "general call
address", ie a broadcast address.  The I2C specification states that the
format of a general call uses at least 2 bytes, which U-Boot's probing
routine does not adhere to.

Not probing device address 0 will prevent possible issues with devices
that accept general calls.  Additionally, this change shouldn't reduce
POST coverage since each I2C device should still be accessed via its
own, unique address.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Acked-by: Heiko Schocher <hs@denx.de>
Acked-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>