rtc: allow rtc_set to return an error and use it in cmd_date

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
diff --git a/board/bmw/m48t59y.c b/board/bmw/m48t59y.c
index a1a85d0..4e83b90 100644
--- a/board/bmw/m48t59y.c
+++ b/board/bmw/m48t59y.c
@@ -299,8 +299,7 @@
 	return 0;
 }
 
-void
-rtc_set( struct rtc_time *tmp )
+int rtc_set( struct rtc_time *tmp )
 {
 	m48_tod_set(tmp->tm_year,		/* 1980-2079 */
 		    tmp->tm_mon,		/* 01-12 */
@@ -315,6 +314,7 @@
 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 #endif
 
+	return 0;
 }
 
 void
diff --git a/board/cray/L1/L1.c b/board/cray/L1/L1.c
index f0dfa07..49a9e5e 100644
--- a/board/cray/L1/L1.c
+++ b/board/cray/L1/L1.c
@@ -181,9 +181,9 @@
 {
 	return 0;
 }
-void rtc_set (struct rtc_time *tmp)
+int rtc_set (struct rtc_time *tmp)
 {
-	return;
+	return 0;
 }
 void rtc_reset (void)
 {
diff --git a/board/etin/debris/phantom.c b/board/etin/debris/phantom.c
index 263da6b..48b81f7 100644
--- a/board/etin/debris/phantom.c
+++ b/board/etin/debris/phantom.c
@@ -254,7 +254,7 @@
 	return 0;
 }
 
-void rtc_set( struct rtc_time *tmp )
+int rtc_set( struct rtc_time *tmp )
 {
 	if (phantom_flag < 0)
 		phantom_flag = get_phantom_flag();
@@ -307,6 +307,8 @@
 		/* unlock clock registers after read */
 		rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));
 	}
+
+	return 0;
 }
 
 #endif
diff --git a/board/mousse/m48t59y.c b/board/mousse/m48t59y.c
index 2c1e6cf..beb26fe 100644
--- a/board/mousse/m48t59y.c
+++ b/board/mousse/m48t59y.c
@@ -299,8 +299,7 @@
 	return 0;
 }
 
-void
-rtc_set( struct rtc_time *tmp )
+int rtc_set( struct rtc_time *tmp )
 {
 	m48_tod_set(tmp->tm_year,		/* 1980-2079 */
 		    tmp->tm_mon,		/* 01-12 */
@@ -315,6 +314,7 @@
 		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 #endif
 
+	return 0;
 }
 
 void