package/syslogd: workaround a compiler bug with CS powerpc 2012.03

The O3 optimization triggers a compiler bug with this toolchain,
change it with 02.

Fixes:
http://autobuild.buildroot.net/results/2fb/2fb94ecfdc32761a09da35e6fcbdd512847ec911



Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>