i2c: Shrink struct i2c_client

This shrinks the size of "struct i2c_client" by 40 bytes:

 - Substantially shrinks the string used to identify the chip type
 - The "flags" don't need to be so big
 - Removes some internal padding

It also adds kerneldoc for that struct, explaining how "name" is really a
chip type identifier; it's otherwise potentially confusing.

Because the I2C_NAME_SIZE symbol was abused for both i2c_client.name
and for i2c_adapter.name, this needed to affect i2c_adapter too.  The
adapters which used that symbol now use the more-obviously-correct
idiom of taking the size of that field.

JD: Shorten i2c_adapter.name from 50 to 48 bytes while we're here, to
avoid wasting space in padding.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/i2c/busses/i2c-pasemi.c

@@ -358,7 +358,7 @@ static int __devinit pasemi_smb_probe(struct pci_dev *dev,
 	}
 
 	smbus->adapter.owner = THIS_MODULE;
-	snprintf(smbus->adapter.name, I2C_NAME_SIZE,
+	snprintf(smbus->adapter.name, sizeof(smbus->adapter.name),
 		 "PA Semi SMBus adapter at 0x%lx", smbus->base);
 	smbus->adapter.class = I2C_CLASS_HWMON;
 	smbus->adapter.algo = &smbus_algorithm;