util/docker/Makefile: Add missing separator

Build using docker results in error: Makefile:86: *** missing separator.

Add space after ifeq.

Tested: Building Facebook FBG1701 binary.

Change-Id: Ib42abe966e67dac380173ec982c9f6bd4cf074cc
Signed-off-by: Frans Hendriks <fhendriks@eltan.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47992
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Wim Vervoorn <wvervoorn@eltan.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/util/docker/Makefile b/util/docker/Makefile
index 8b1d0ef..cf14c0d 100644
--- a/util/docker/Makefile
+++ b/util/docker/Makefile
@@ -83,7 +83,7 @@
 	@$(MAKE) clean-coreboot-images
 
 docker-cleanall: test-docker
-ifeq($(Y),1)
+ifeq ($(Y),1)
 	@if [ -n "$$($(DOCKER) ps -a | grep -v "CONTAINER")" ]; then \
 		$(DOCKER) kill $$($(DOCKER) ps | grep -v "CONTAINER" | sed 's|\s.*$$||') ; \
 		$(DOCKER) rm $$($(DOCKER) ps -a | grep -v "CONTAINER" | sed 's|\s.*$$||'); \