Update clc_mul_hi.cl

Author: rjodinchr

libclc/clc/lib/clspv/integer/clc_mul_hi.cl

@@ -0,0 +1,5 @@
+/*
+Opt-out of libclc mul_hi implementation for clspv.
+clspv has an internal implementation that does not required using a bigger data size.
+That implementation is based on OpMulExtended which is SPIR-V specific, thus it cannot be written in OpenCL-C.
+*/