slw: fix typo in slw dump comment

We have an typo in a @fwts-advice field, which means it's carried
through to the generated fwts olog data. This change fixes the typo so
that the advice output from fwts is correct.

CC: Deb McLemore <debmc@linux.vnet.ibm.com>
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

hw/slw.c

@@ -1271,7 +1271,7 @@ static void slw_dump_timer_ffdc(void)
 
 	/**
 	 * @fwts-label SLWRegisterDump
-	 * @fwts-advice An error condition occured in sleep/winkle
+	 * @fwts-advice An error condition occurred in sleep/winkle
 	 * engines timer state machine. Dumping debug information to
 	 * root-cause. OPAL/skiboot may be stuck on some operation that
 	 * requires SLW timer state machine (e.g. core powersaving)