spl: mmc: avoid including errno.h twice

Each include should only be included once.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>

common/spl/spl_mmc.c

@@ -12,7 +12,6 @@
 #include <spl_load.h>
 #include <linux/compiler.h>
 #include <errno.h>
-#include <errno.h>
 #include <mmc.h>
 #include <image.h>
 #include <imx_container.h>