i2c: octeon: Increase retry default and use fixed timeout value

Convert the adapter timeout to 2 ms independently of depending on CONFIG_HZ.
CONFIG_HZ is 100 for MIPS Cavium-Octeon so the timeout value is not changed.

Also set retries to 5 to improve robustness.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>