gcc-5.3/gcc-4.9:Reuse -fdebug-prefix-map to replace -ffile-prefix-map

gcc-5.3/gcc-4.9:Reuse -fdebug-prefix-map to replace -ffile-prefix-map

The oe-core may use external toolchain for compiling,
which did not support -ffile-prefix-map.

Since we use -fdebug-prefix-map to do the same thing,
so we could reuse it to replace -ffile-prefix-map.

[YOCTO #7058]

(From OE-Core rev: cec9ee4d32d96e8717f63268a00888260eae1b30)

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>