w1: ds2408: Fix typo after 49695ac4 (reset on output_write retry with readback)

Fix a typo in commit:
49695ac4 w1: ds2408: reset on output_write retry with readback

Fixes: 49695ac4 ("w1: ds2408: reset on output_write retry with readback")
Reported-by: NPhil Elwell <phil@raspberrypi.org>
Cc: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: NMariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/w1/slaves/w1_ds2408.c

@@ -138,7 +138,7 @@ static ssize_t status_control_read(struct file *filp, struct kobject *kobj,
 		W1_F29_REG_CONTROL_AND_STATUS, buf);
 }
 
-#ifdef fCONFIG_W1_SLAVE_DS2408_READBACK
+#ifdef CONFIG_W1_SLAVE_DS2408_READBACK
 static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
 {
 	u8 w1_buf[3];