i2c: fix read-only I2C transfers on STM32F0/F3
i2c: fix read-only I2C transfers on STM32F0/F3

Ensure that we put a proper start bit if the transfer only contains a
read but has the start flag set.

Signed-off-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>

BRANCH=smaug
BUG=chrome-os-partner:40919
TEST=On Smaug (P6), at the Linux prompt, do
"cat /sys/class/power_supply/bq27742-0/current_now" and see a proper
value rather than an error.

Change-Id: I10cc9907476b3cfb006f2c1540688139366c9195
Reviewed-on: https://chromium-review.googlesource.com/275079
Trybot-Ready: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Tested-by: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Reviewed-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>
Commit-Queue: Vincent Palatin <70a9964ec8fd10b0b08fcc8623c2add25ddf99ac@chromium.org>
Tested-by: Puthikorn Voravootivat <6b0bf59b07ec88a47755d311f85101e4220afc86@chromium.org>

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