i2c: rk3x: report number of messages transmitted

[ Upstream commit c6cbfb91 ]

master_xfer() method should return number of i2c messages transferred,
but on Rockchip we were usually returning just 1, which caused trouble
with users that actually check number of transferred messages vs.
checking for negative error codes.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>