i2c: Simplify i2c_parent_is_i2c_adapter

Only i2c devices can have their type set to i2c_adapter_type, so
testing the bus type is redundant.

Signed-off-by: Jean Delvare <[e-mail]>
Cc: Michael Lawnick <[e-mail]>

include/linux/i2c.h

···
 static inline int i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
 {
 	return adapter->dev.parent != NULL
-		&& adapter->dev.parent->bus == &i2c_bus_type
 		&& adapter->dev.parent->type == &i2c_adapter_type;
 }