mx6qsabre{sd, auto}: Fix environment as 'mmc rescan' takes no arguments

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Acked-by: Fabio Estevam <fabio.estevam@freescale.com>

include/configs/mx6qsabre_common.h

@@ -148,7 +148,7 @@
 
 #define CONFIG_BOOTCOMMAND \
 	"mmc dev ${mmcdev};" \
-	"if mmc rescan ${mmcdev}; then " \
+	"if mmc rescan; then " \
 		"if run loadbootscript; then " \
 		"run bootscript; " \
 		"else " \