i2c: octeon: Cleanup i2c-octeon driver

Cleanup only without functional change.

- removed DRV_VERSION
- defines: use defines instead of plain values,
  use BIT_ULL macro, add comments
- rename waitqueue return value to time_left
- sort local variables by length
- fix indentation and whitespace errors
- make function return void if the result is not used
  (octeon_i2c_stop, octeon_i2c_set_clock)
- remove debug code from octeon_i2c_stop
- renamed some functions for readability
- update copyright

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