i.MX6: engicam: gpr_init can be called only for some architecture

Fix an invalid usage of the gpr_init function for the imx6ul
architecture

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Acked-by: Jagan Teki <jagan@amarulasolutions.com>

board/engicam/common/spl.c

@@ -414,7 +414,8 @@ void board_init_f(ulong dummy)
 	/* setup AIPS and disable watchdog */
 	arch_cpu_init();
 
-	gpr_init();
+	if (!(is_mx6ul()))
+		gpr_init();
 
 	/* iomux */
 	SETUP_IOMUX_PADS(uart_pads);