[ARM] 4650/1: AT91: New-style init of I2C, support for i2c-gpio

The AT91 I2C driver is currently marked as "broken" due to hardware
issues.  This patch enables AT91-based platforms to also use the
bitbanged GPIO for I2C.

This updates platform setup logic (setting up an i2c-gpio device
using the same pins as the i2c-at91 device, unless only the BROKEN
driver is enabled).

Also make use of the new-style initialization of I2C devices using
i2c_register_board_info().

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>