docs: i2c: smbus-protocol: properly name start and stop conditions

In I2C there is no such thing as a "start bit" or a "stop bit". Use the
proper naming: "start condition" and "stop condition".
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

@@ -35,8 +35,8 @@ Key to symbols
 ==============
 
 =============== =============================================================
-S     (1 bit) : Start bit
-P     (1 bit) : Stop bit
+S             : Start condition
+P             : Stop condition
 Rd/Wr (1 bit) : Read/Write bit. Rd equals 1, Wr equals 0.
 A, NA (1 bit) : Accept and reverse accept bit.
 Addr  (7 bits): I2C 7 bit address. Note that this can be expanded as usual to