i2c: exynos5: remove extra line and fix an assignment

This patch does the following in exynos5_i2c_message_start() function
1. Fixes an assignment
   As, "i2c_auto_conf" is initialized to '0' at the beginning of the
   function and HSI2C_READ_WRITE is defined as (1u << 16)

   Using "|=" for the first assignment is more readable.

2. Removes an extra line

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>