actua1/actua2/actua3: Fix multiple unused variable warnings

- actua1:
	actux1.c: In function 'checkboard':
	actux1.c:92: warning: unused variable 'revision'

- actua2:
	actux2.c: In function 'checkboard':
	actux2.c💯 warning: unused variable 's'
	actux2.c:99: warning: unused variable 'revision'
	actux2.c: In function 'reset_phy':
	actux2.c:130: warning: unused variable 'i'

- actua3:
	actux3.c: In function 'checkboard':
	actux3.c:114: warning: unused variable 'revision'

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

board/actux1/actux1.c

@@ -89,7 +89,6 @@ int board_init (void)
  */
 int checkboard (void)
 {
-	char revision;
 	char *s = getenv ("serial#");
 
 	puts ("Board: AcTux-1 rev.");

board/actux2/actux2.c

@@ -96,11 +96,15 @@ int board_init (void)
  */
 int checkboard (void)
 {
-	char revision;
 	char *s = getenv ("serial#");
 
 	puts ("Board: AcTux-2 rev.");
 	putc (ACTUX2_BOARDREL + 'A' - 1);
+
+	if (s != NULL) {
+		puts (", serial# ");
+		puts (s);
+	}
 	putc ('\n');
 
 	return (0);
@@ -127,8 +131,6 @@ u32 get_board_rev (void)
 
 void reset_phy (void)
 {
-	int i;
-
 	/* init IcPlus IP175C ethernet switch to native IP175C mode */
 	miiphy_write ("NPE0", 29, 31, 0x175C);
 }

board/actux3/actux3.c

@@ -111,7 +111,6 @@ int board_init (void)
  */
 int checkboard (void)
 {
-	char revision;
 	char *s = getenv ("serial#");
 
 	puts ("Board: AcTux-3 rev.");