coding style: add missing space when split strings

Long strings are split across few lines; usually split occurs at
the white space between two words.
Check that the space between the two words is still present.
While there, adjust the amount of space between words.

Issue identified by checkpatch script from Linux kernel v5.1 using
the command

	find src/ -type f -exec ./tools/scripts/checkpatch.pl \
	-q --types MISSING_SPACE -f {} \;

Change-Id: I28b9a65564195ba967051add53d1c848c7b8fb30
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5620
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Tested-by: jenkins

src/rtos/linux.c

@@ -1379,8 +1379,8 @@ static int linux_thread_packet(struct connection *connection, char const *packet
 						 target->rtos->
 						 current_threadid)
 				&& (target->rtos->current_threadid != -1))
-					LOG_WARNING("WARNING! current GDB thread do not match"
-							"current thread running."
+					LOG_WARNING("WARNING! current GDB thread do not match "
+							"current thread running. "
 							"Switch thread in GDB to threadid %d",
 							(int)ct->threadid);