binman: Add support for SCP firmware

Add an entry type for a firmware blob for a System Control Processor,
given by an entry arg. This firmware is a raw binary blob.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/Makefile b/Makefile
index 2b21675..1502a74 100644
--- a/Makefile
+++ b/Makefile
@@ -1331,6 +1331,7 @@
 		-I arch/$(ARCH)/dts -a of-list=$(CONFIG_OF_LIST) \
 		-a atf-bl31-path=${BL31} \
 		-a default-dt=$(default_dt) \
+		-a scp-path=$(SCP) \
 		$(BINMAN_$(@F))
 
 OBJCOPYFLAGS_u-boot.ldr.hex := -I binary -O ihex