tools build: No need to make libapi for perf explicitly

The perf build handles its dependencies by itself.

Also renaming libapi libapikfs to libapi as it got
changed just recently.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: linux-kbuild@vger.kernel.org
Link: http://lkml.kernel.org/r/1429389280-18720-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/Makefile

@@ -47,10 +47,10 @@ cgroup firewire hv guest usb virtio vm net: FORCE
 liblockdep: FORCE
 	$(call descend,lib/lockdep)
 
-libapikfs: FORCE
+libapi: FORCE
 	$(call descend,lib/api)
 
-perf: libapikfs FORCE
+perf: FORCE
 	$(call descend,$@)
 
 selftests: FORCE
@@ -97,10 +97,10 @@ cgroup_clean hv_clean firewire_clean lguest_clean usb_clean virtio_clean vm_clea
 liblockdep_clean:
 	$(call descend,lib/lockdep,clean)
 
-libapikfs_clean:
+libapi_clean:
 	$(call descend,lib/api,clean)
 
-perf_clean: libapikfs_clean
+perf_clean:
 	$(call descend,$(@:_clean=),clean)
 
 selftests_clean: