utils/crossgcc: Refactor Makefiles for separate arm/i386.

Refactor Makefile build system as decompartmentalise armv7a and i386
targets from crossgcc.

Change-Id: If93f62050810ba594c9925a9eb8ba9d04bc76459
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/4008
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
diff --git a/Makefile.inc b/Makefile.inc
index ec78540..19ba294 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -369,11 +369,23 @@
 	git config remote.origin.push HEAD:refs/for/master
 	(git config --global user.name >/dev/null && git config --global user.email >/dev/null) || (printf 'Please configure your name and email in git:\n\n git config --global user.name "Your Name Comes Here"\n git config --global user.email your.email@example.com\n'; exit 1)
 
-crossgcc: clean-for-update
-	$(MAKE) -C util/crossgcc build-without-gdb
+crossgcc: crossgcc-i386 crossgcc-arm
 
-crosstools: clean-for-update
-	$(MAKE) -C util/crossgcc build
+.PHONY: crossgcc-i386 crossgcc-arm
+crossgcc-i386: clean-for-update
+	$(MAKE) -C util/crossgcc build-i386-without-gdb
+
+crossgcc-arm: clean-for-update
+	$(MAKE) -C util/crossgcc build-armv7a-without-gdb
+
+crosstools: crosstools-i386
+
+.PHONY: crosstools-i386 crosstools-arm
+crosstools-i386: clean-for-update
+	$(MAKE) -C util/crossgcc build-i386
+
+crosstools-arm: clean-for-update
+	$(MAKE) -C util/crossgcc build-armv7a
 
 crossgcc-clean: clean-for-update
 	$(MAKE) -C util/crossgcc clean