Revert "tools lib lk: Fix for cross build"

This reverts commit 079787f209416416383c74ea5d5044be2d586f5e.

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

commit 3c4797d46c14fa0c7cf733a77bd4b28875078b53
Author: Rabin Vincent <[e-mail]>
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: Joonsoo Kim <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/lib/lk/Makefile

···
 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=