mainboard/aopen: Use C89 comments style & remove commented code

Change-Id: I0014fc030888d71f7951c97bccc7cef0e1c45186
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/16922
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/mainboard/aopen/dxplplusu/fadt.c b/src/mainboard/aopen/dxplplusu/fadt.c
index cfeb2e2..418d547 100644
--- a/src/mainboard/aopen/dxplplusu/fadt.c
+++ b/src/mainboard/aopen/dxplplusu/fadt.c
@@ -66,7 +66,7 @@
 
 	fadt->pm1_evt_len = 4;
 	fadt->pm1_cnt_len = 2;
-	// XXX: pm2_cnt_len is probably wrong. find out right value (hint: it's != 0)
+	/* XXX: pm2_cnt_len is probably wrong. find out right value (hint: it's != 0) */
 	fadt->pm2_cnt_len = 0;
 	fadt->pm_tmr_len = 4;
 	fadt->gpe0_blk_len = 8;