Fix parallel build for cmm

This is the wildcard recipe for the "all" target:

%/all:
	$(MAKE) -C $* all

The following recipe for "cmm/all" had priority over the more general
recipe for the "%/all" target.

cmm/all: fci/lib/install
	@

The resulting recipe for "cmm/all" was basically a noop.  Nothing got
built.

After the "all" target has been remade, Make would execute the "install"
recipe which basically runs the following two commands in parallel.

make -C cmm DESTDIR=staging/ install
make -C cmm DESTDIR=target/ install

The Makefile in the "cmm" subdirectory defines the "all" target as a
prerequisite of the "install" target and therefore builds the same
before running the "install" recipe. As a result, two instances of make
are trying to re-make the "all" target at the same time which wreaks
havoc.

To fix this problem, change the definition of "cmm/all" from a recipe to
a definition of a dependency. Make will now run a single instance of
"$(MAKE) -C $* all" before running two instances for the "install"
targets concurrently.

Change-Id: I20561c6bd0fbeeeaaf30bbffb6497bfdc9b4f31f
diff --git a/Makefile b/Makefile
index f411ac9..fde0a8d 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,6 @@
 $(addsuffix /install,$(KMOD_DIRS)): %/install: %/all
 
 cmm/all: fci/lib/install
-	@
 
 %/all:
 	$(MAKE) -C $* all