Add missing option -r to usage summary

Reported by Jaromir Capik.


git-svn-id: http://lm-sensors.org/svn/i2c-tools/branches/i2c-tools-3.1@6202 7894878c-1315-0410-8ee3-d5d059ff63e0

tools/i2cset.c

@@ -38,7 +38,7 @@ static void help(void) __attribute__ ((noreturn));
 static void help(void)
 {
 	fprintf(stderr,
-		"Usage: i2cset [-f] [-y] [-m MASK] I2CBUS CHIP-ADDRESS DATA-ADDRESS [VALUE] ... [MODE]\n"
+		"Usage: i2cset [-f] [-y] [-m MASK] [-r] I2CBUS CHIP-ADDRESS DATA-ADDRESS [VALUE] ... [MODE]\n"
 		"  I2CBUS is an integer or an I2C bus name\n"
 		"  ADDRESS is an integer (0x03 - 0x77)\n"
 		"  MODE is one of:\n"