i2c: omap: Clear ARDY bit twice

Initially commit cb527ede
"i2c-omap: Double clear of ARDY status in IRQ handler"
added a workaround for undocumented errata ProDB0017052.
But then commit 1d7afc95
"i2c: omap: ack IRQ in parts" refactored code and missed
one of ARDY clearings. So current code violates errata.
It causes often i2c bus timeouts on my Pandaboard.

This patch adds a second clearing in place.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Taras Kondratiuk <taras.kondratiuk@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org