pckage/upmpdcli: disable for powerpc CS toolchains

Those toolchains use gcc <= 4.5, which is too old as they are missing
range-based for-loops, only introduced with gcc-4.6.

Fixes:
    http://autobuild.buildroot.net/results/f00/f00fa9b83718abaffd1f52dcd50e582434b3c5e2/



Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Cc: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>