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>
diff --git a/drivers/video/matrox/i2c-matroxfb.c b/drivers/video/matrox/i2c-matroxfb.c
index 5ec718a..4baab7b 100644
--- a/drivers/video/matrox/i2c-matroxfb.c
+++ b/drivers/video/matrox/i2c-matroxfb.c
@@ -111,7 +111,7 @@
 	b->mask.data = data;
 	b->mask.clock = clock;
 	b->adapter = matrox_i2c_adapter_template;
-	snprintf(b->adapter.name, I2C_NAME_SIZE, name,
+	snprintf(b->adapter.name, sizeof(b->adapter.name), name,
 		minfo->fbcon.node);
 	i2c_set_adapdata(&b->adapter, b);
 	b->adapter.algo_data = &b->bac;