i2c-algo-bit: Add pre- and post-xfer hooks

Drivers might have to do random things before and/or after I2C
transfers. Add hooks to the i2c-algo-bit implementation to let them do
so.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Alex Deucher <alexdeucher@gmail.com>

include/linux/i2c-algo-bit.h

@@ -36,6 +36,8 @@ struct i2c_algo_bit_data {
 	void (*setscl) (void *data, int state);
 	int  (*getsda) (void *data);
 	int  (*getscl) (void *data);
+	int  (*pre_xfer)  (struct i2c_adapter *);
+	void (*post_xfer) (struct i2c_adapter *);
 
 	/* local settings */
 	int udelay;		/* half clock cycle time in us,