siteinfo: Rework the siteinfo for powerpc to fix uclibc fallout
I believe that powerpc-linux is now a common file across 32bit/64bit
linux for powerpc be it uclibc or glibc. I compared the differences
between powerpc-linux-uclibc and powerpc-linux files and it
powerpc-linux was more uptodate and all the new stuff it had was needed
for uclibc anyway so we do not need to keep exact copy of powerpc-linux
as powerpc-linux-uclibc instead we use powerpc-linux for powerpc/uclibc
targets.
Secondly linux specific files were added in archinfo dictionary
which I think logically belongs to targetinfo dictionary therefore
moved them to targetinfo
