[PATCH] I2C: add Hydra i2c bus driver

[PATCH] I2C: add Hydra i2c bus driver

Here's a new version, incorporating these comments, and making a few more
changes:
  - Use struct definition in <asm/hydra.h> instead of #defined offset
  - Remove flushes are register writes, they are no longer needed
  - Use pci_resource_start() instead of dev->resource[].start
  - ioremap() the whole resource instead of the first 256 bytes
  - Check for errors returned by ioremap() and i2c_bit_add_bus()
  - Add resource management
  - Call iounmap() in hydra_remove() instead of in i2c_hydra_exit()
  - Let I2C_HYDRA depend on I2C and select I2C_ALGOBIT instead of depending on
    I2C_ALGOBIT