mxs: Silence elftosb

The elftosb tool is now called with -d switch, which produces debug
output to the stdout. The debug output is completely useless for
regular operation, so silence it.
Signed-off-by: NMarek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: NOtavio Salvador <otavio@ossystems.com.br>

Makefile

@@ -495,7 +495,7 @@ $(obj)u-boot.ais:       $(obj)spl/u-boot-spl.bin $(obj)u-boot.img
 ELFTOSB_TARGET-$(CONFIG_MX28) = imx28
 
 $(obj)u-boot.sb:       $(obj)u-boot.bin $(obj)spl/u-boot-spl.bin
-		elftosb -zdf $(ELFTOSB_TARGET-y) -c $(TOPDIR)/$(CPUDIR)/$(SOC)/u-boot-$(ELFTOSB_TARGET-y).bd \
+		elftosb -zf $(ELFTOSB_TARGET-y) -c $(TOPDIR)/$(CPUDIR)/$(SOC)/u-boot-$(ELFTOSB_TARGET-y).bd \
 			-o $(obj)u-boot.sb
 
 # On x600 (SPEAr600) U-Boot is appended to U-Boot SPL.