gcc-cross-canadian: Install LTO linker plugin to BFD searchable location

This helps binutils provided tools ar/ranlib/nm to find the LTO linker
plugin automatically as well which makes it equivalent to gcc-ar/gcc-nm/gcc-ranlib

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