i2c: Restore i2c_smbus_read_block_data

Add back the i2c_smbus_read_block_data helper function, it is needed
by the upcoming lm93 hardware monitoring driver and possibly others.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 3fe2ad3..cae7d61 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -82,6 +82,9 @@
 extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command);
 extern s32 i2c_smbus_write_word_data(struct i2c_client * client,
                                      u8 command, u16 value);
+/* Returns the number of read bytes */
+extern s32 i2c_smbus_read_block_data(struct i2c_client *client,
+				     u8 command, u8 *values);
 extern s32 i2c_smbus_write_block_data(struct i2c_client * client,
 				      u8 command, u8 length,
 				      const u8 *values);