docs: i2c: smbus-protocol: fix kernel-doc function syntax

This clarifies these are functions (and would/will adds a hyperlink to the
function documentation if/when documented).
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/i2c/smbus-protocol.rst

@@ -118,7 +118,7 @@ byte. But this time, the data is a complete word (16 bits)::
 
 Functionality flag: I2C_FUNC_SMBUS_READ_WORD_DATA
 
-Note the convenience function i2c_smbus_read_word_swapped is
+Note the convenience function i2c_smbus_read_word_swapped() is
 available for reads where the two data bytes are the other way
 around (not SMBus compliant, but very popular.)
 
@@ -152,7 +152,7 @@ specified through the Comm byte.::
 
 Functionality flag: I2C_FUNC_SMBUS_WRITE_WORD_DATA
 
-Note the convenience function i2c_smbus_write_word_swapped is
+Note the convenience function i2c_smbus_write_word_swapped() is
 available for writes where the two data bytes are the other way
 around (not SMBus compliant, but very popular.)