i2c: i801: Use managed pcim_* PCI device initialization and reservation

Simplifies the code a bit and makes easier to disable PCI device on driver
detach by removing the pcim_pin_device() call in the future if needed.

Reason why i2c-i801.c doesn't ever call pci_disable_device() was because it
made some systems to hang during power-off. See commit d6fcb3b9


("[PATCH] i2c-i801.c: don't pci_disable_device() after it was just enabled")
and
http://marc.info/?l=linux-kernel&m=115160053309535&w=2

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>