Adds loongarch simd extension(LSX LASX) configure test and -feature-lsx and -feature-lasx configure options. Add detection of LSX and LASX at run-time in qsimd.cpp. Change-Id: I63eab2f4f45c306b672a89b376e0cbc01da0df83 Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io> Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>