powerpc: Remove pie flags from compiler cmdline

powerpc: Remove pie flags from compiler cmdline

Original approach to add -no-<pie> flags cause link time behavior changes
where packages start to lose the -fPIC -DPIC in compiler cmdline and this
list keeps growing as we build more and more packages,

Instead lets just remove the options we dont need from SECURITY_CFLAGS
this makes it more robust and less intrusive

This also means we do not need to re-add pic options as we started to do
for affected packages

(From OE-Core rev: 1520f5a345fd03d46f33f0efaf76191e96344bec)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>