Revert "tools lib lk: Fix for cross build"

This reverts commit 079787f2.

Below commit already resolve a cross build problem.
I have been noticed this too lately.

    commit 3c4797d4
    Author: Rabin Vincent <rabin@rab.in>
    Date:   Fri May 17 22:27:44 2013 +0200

    tools lib lk: Respect CROSS_COMPILE

    Make lk use CROSS_COMPILE, in order to be able to cross compile perf
    again.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1373936614-22224-1-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/lk/Makefile

@@ -3,21 +3,6 @@ include ../../scripts/Makefile.include
 CC = $(CROSS_COMPILE)gcc
 AR = $(CROSS_COMPILE)ar
 
-# Makefiles suck: This macro sets a default value of $(2) for the
-# variable named by $(1), unless the variable has been set by
-# environment or command line. This is necessary for CC and AR
-# because make sets default values, so the simpler ?= approach
-# won't work as expected.
-define allow-override
-  $(if $(or $(findstring environment,$(origin $(1))),\
-            $(findstring command line,$(origin $(1)))),,\
-    $(eval $(1) = $(2)))
-endef
-
-# Allow setting CC and AR, or setting CROSS_COMPILE as a prefix.
-$(call allow-override,CC,$(CROSS_COMPILE)gcc)
-$(call allow-override,AR,$(CROSS_COMPILE)ar)
-
 # guard against environment variables
 LIB_H=
 LIB_OBJS=