i2c: exynos5: remove an unnecessary read of FIFO_STATUS register

This patch removes an extra read of FIFO_STATUS register in the interrrupt
service routine. Which is read again before the actual use.

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