tools/turbostat: allow user to alter DESTDIR and PREFIX

tools/turbostat: allow user to alter DESTDIR and PREFIX

Orabug: 24811361

When run
	make -C tools DESTDIR=/my/nice/dir turbostat_install
get a message
	install: cannot create regular file '/usr/bin/turbostat': Permission denied

Allow user to alter DESTDIR and PREFIX variables.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit ac485cb4b3b79fb7ef979cb243ee16e1a1ffa767)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Signed-off-by: Dhaval Giani <dhaval.giani@oracle.com>