[ARM] 4246/1: i2c-pxa: add adapter class to platform specific data

Reposted patch for kernel 2.6.21-rc2.

The driver i2c-pxa doesn't set the class member in i2c_adapter, which
is used to register the I2C adapter. The hwmon (sensors) drivers (e.g.
adm1021) that are connected to a i2c-pxa adapter don't attach because
they expect that the adapter supports class I2C_CLASS_HWMON.

This patch adds functionality to allow platforms to set the class and
pass it as platform_data to the i2c-pxa driver. Sample usage in
platform code:

static struct i2c_pxa_platform_data my_i2c_platform_data = {
	.class = I2C_CLASS_HWMON
};

static void __init my_platform_init(void)
{
	(void) platform_add_devices(devices, ARRAY_SIZE(devices));

	pxa_set_i2c_info(&my_i2c_platform_data);
}

Signed-off-by: Matej Kenda <matej.kenda@hermes-softlab.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>