imx: kontron-sl-mx6ul: Fix include statements for local header

The header from the local directory should use double quotes instead
of brackets. Otherwise the compiler might not search the local
directory.

Fixes: 93935acc6f ("imx: imx6ul: kontron-sl-mx6ul: Select correct boot and env device")
Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>

board/kontron/sl-mx6ul/sl-mx6ul-common.c

@@ -6,7 +6,7 @@
 #include <asm/types.h>
 #include <asm/arch/sys_proto.h>
 
-#include <sl-mx6ul-common.h>
+#include "sl-mx6ul-common.h"
 
 bool sl_mx6ul_is_spi_nor_boot(void)
 {

board/kontron/sl-mx6ul/sl-mx6ul.c

@@ -9,7 +9,8 @@
 #include <env_internal.h>
 #include <fdt_support.h>
 #include <phy.h>
-#include <sl-mx6ul-common.h>
+
+#include "sl-mx6ul-common.h"
 
 DECLARE_GLOBAL_DATA_PTR;
 

board/kontron/sl-mx6ul/spl.c

@@ -18,7 +18,8 @@
 #include <linux/sizes.h>
 #include <linux/errno.h>
 #include <mmc.h>
-#include <sl-mx6ul-common.h>
+
+#include "sl-mx6ul-common.h"
 
 DECLARE_GLOBAL_DATA_PTR;