cosmetic: clarify c_iflag in osmo_serial_init()

We first set the ISTRIP bit only to remove it in the next line.
Let's try to avoid confusing the reader.

Change-Id: Icba43dd4b6dc4f9c7f8fcf91d24b3baac4e0c74a
diff --git a/src/serial.c b/src/serial.c
index 1b5a4cf..31cb81d 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -97,7 +97,7 @@
 	tio.c_cflag &= ~(PARENB | CSTOPB | CSIZE | CRTSCTS);
 	tio.c_cflag |=  (CREAD | CLOCAL | CS8);
 	tio.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
-	tio.c_iflag |=  (INPCK | ISTRIP);
+	tio.c_iflag |=  (INPCK);
 	tio.c_iflag &= ~(ISTRIP | IXON | IXOFF | IGNBRK | INLCR | ICRNL | IGNCR);
 	tio.c_oflag &= ~(OPOST | ONLCR);