This matches the method implemented in i2cdetect(8) when using its -q
option.

With this change an rx8130 RTC is detectable using i2c_probe. This
failed before because this chip acks the first byte (containing its
address and the R/̅W bit) but nacks the following 0 (representing the
target address to write nothing to) which makes i2c_write_reg() return
with an error and so the chip is not listed as available.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>