qt5bse: configure: fix gold linker detection

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



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.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>