tools/power/cpupower: Add 64 bit library detection

The kernel-tools-lib rpm is installing the library to /usr/lib64, and not
/usr/lib as the cpupower Makefile is doing in the kernel tree.  This
resulted in a conflict between the two libraries.  After looking at how
other tools installed libraries, and looking at the perf code in
tools/perf it looks like installing to /usr/lib64 for 64-bit arches is the
correct thing to do.

Checks with 'ldd cpupower' on SLES, RHEL, Fedora, and Ubuntu result in
the correct binary AFAICT:

[root@testsystem cpupower]# ldd cpupower | grep cpupower
        libcpupower.so.0 => /lib64/libcpupower.so.0 (0x00007f1dab447000)

Commit ac5a181d ("cpupower: Add cpuidle parts into library") added a
new cpupower library version.  On Fedora, executing the cpupower binary
then resulted in this error

[root@testsystem cpupower]# ./cpupower monitor
./cpupower: symbol lookup error: ./cpupower: undefined symbol:
get_cpu_topology

64-bit libraries should be installed to /usr/lib64, and other libraries
should be installed to /usr/lib.

This code was taken from the perf Makefile.config which supports /usr/lib
and /usr/lib64.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/power/cpupower/Makefile

@@ -30,6 +30,8 @@ OUTDIR := $(shell cd $(OUTPUT) && /bin/pwd)
 $(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
 endif
 
+include ../../scripts/Makefile.arch
+
 # --- CONFIGURATION BEGIN ---
 
 # Set the following to `true' to make a unstripped, unoptimized
@@ -79,7 +81,11 @@ bindir ?=	/usr/bin
 sbindir ?=	/usr/sbin
 mandir ?=	/usr/man
 includedir ?=	/usr/include
+ifeq ($(IS_64_BIT), 1)
+libdir ?=	/usr/lib64
+else
 libdir ?=	/usr/lib
+endif
 localedir ?=	/usr/share/locale
 docdir ?=       /usr/share/doc/packages/cpupower
 confdir ?=      /etc/