Makefile: add support for DESTDIR.
Makefile: add support for DESTDIR.

Signed-off-by: Davide Pesavento <12972e6f3f5e3567d4d7a35a993678077bef5660@gmail.com>
Signed-off-by: Luis R. Rodriguez <79e6b8107a8aa3944e09fad43634662ac3b91a0b@atheros.com>

CyanogenMod/android_external_crda,idor/crda,CyanogenMod/android_external_crda,ThirdProject/android_external_crda,idor/crda,ThirdProject/android_external_crda