qt5-creator: Enable clang plugin support when clang is used as toolchain
qt5-creator: Enable clang plugin support when clang is used as toolchain

Signed-off-by: Khem Raj <729d64b6f67515e258459a5f6d20ec88b2caf8df@gmail.com>

sapiippo/meta-qt5,schnitzeltony/meta-qt5,meta-qt5/meta-qt5,meta-qt5/meta-qt5,schnitzeltony/meta-qt5,sapiippo/meta-qt5