dmp/vortex86ex/southbridge.c: Do not access arrays out of bound

Found by Cppcheck 1.65. Fixes:
[src/southbridge/dmp/vortex86ex/southbridge.c:498]: (error) Array 'rtc[7]' accessed at index 7, which is out of bounds.
[src/southbridge/dmp/vortex86ex/southbridge.c:498]: (error) Array 'bin_rtc[7]' accessed at index 7, which is out of bounds.

Change-Id: I8939fe1b326202bbe2784639b0e591f8ee470eeb
Signed-off-by: Daniele Forsi <dforsi@gmail.com>
Reviewed-on: http://review.coreboot.org/6375
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Andrew Wu <arw@dmp.com.tw>
diff --git a/src/southbridge/dmp/vortex86ex/southbridge.c b/src/southbridge/dmp/vortex86ex/southbridge.c
index b9432f0..a2b1246 100644
--- a/src/southbridge/dmp/vortex86ex/southbridge.c
+++ b/src/southbridge/dmp/vortex86ex/southbridge.c
@@ -494,7 +494,7 @@
 	/* Convert RTC from BCD format to binary. */
 	u8 bin_rtc[7];
 	int i;
-	for (i = 0; i < 8; i++) {
+	for (i = 0; i < 7; i++) {
 		bin_rtc[i] = bcd2dec(rtc[i]);
 	}