imximage.cfg: run files through C preprocessor

The '#' used as comments in the files cause the preprocessor
trouble, so change to /* */.

The mkimage command which uses this preprocessor output
was moved to arch/arm/imx-common/Makefile

.gitignore was updated to ignore .cfgtmp files.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
diff --git a/spl/Makefile b/spl/Makefile
index 6dbb105..d8efad0 100644
--- a/spl/Makefile
+++ b/spl/Makefile
@@ -141,11 +141,8 @@
 	$(OBJTREE)/tools/mkimage -T omapimage -n byteswap \
 		-a $(CONFIG_SPL_TEXT_BASE) -d $< $@
 
-ifneq ($(CONFIG_IMX_CONFIG),)
-$(OBJTREE)/SPL:	$(obj)u-boot-spl.bin
-	$(OBJTREE)/tools/mkimage -n  $(SRCTREE)/$(CONFIG_IMX_CONFIG) -T imximage \
-		-e $(CONFIG_SPL_TEXT_BASE) -d $< $@
-endif
+$(OBJTREE)/SPL : $(obj)u-boot-spl.bin depend
+		$(MAKE) -C $(SRCTREE)/arch/arm/imx-common $@
 
 ALL-y	+= $(obj)u-boot-spl.bin