qtbase: configure: fix gold linker support detection

While the -fuse-ld=gold flag is related to linking, it is an argument to the compiler driver to tell it what linker to execute, NOT an option to tell the linker to behave differently.

So it shouldn't get prefixed with -Wl when passed though the compiler driver.

Fixes http://autobuild.buildroot.net/results/92c/92c3fb4ddb934115b228652bb8c972bb7459bb40/