gcc-4.6: Specify complete paths in require directive

gcc-4.6: Specify complete paths in require directive

This is needed for adjusting meta-linaro where linaro
gcc recipes leverage the core recipe infrastructure and
modifies minimal to keep compatibility with OE-Core
so that any changes in OE-Core gcc recipes does not
trigger changes in meta-linaro.

(From OE-Core rev: cb01b2a4fc82e62eacc4441fddc3fdfb04a3acf3)

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