Makefile: imx: Do not call arch/arm/mach-imx flash.bin generation if BINMAN enabled

Skip running arch/arm/mach-imx flash.bin generation in case BINMAN is
enabled, otherwise the target in arch/arm/mach-imx/Makefile regenerates
the flash.bin again and produces corrupted result.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Peng Fan <peng.fan@oss.nxp.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/Makefile b/Makefile
index 184223e..a69cc08 100644
--- a/Makefile
+++ b/Makefile
@@ -1535,7 +1535,6 @@
 ifeq ($(CONFIG_BINMAN),y)
 flash.bin: spl/u-boot-spl.bin $(INPUTS-y) FORCE
 	$(call if_changed,binman)
-	$(Q)$(MAKE) $(build)=arch/arm/mach-imx $@
 else
 flash.bin: spl/u-boot-spl.bin u-boot.itb FORCE
 	$(Q)$(MAKE) $(build)=arch/arm/mach-imx $@