gallivm: Fix include for LLVMAddPromoteMemoryToRegisterPass

Include llvm-c/Transforms/Utils.h with the newest LLVM 7

Signed-of-by: Mike Lothian <mike@fireburn.co.uk>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Tested-by: Dieter Nützel <Dieter@nuetzel-hh.de>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/auxiliary/gallivm/lp_bld_init.c

@@ -40,6 +40,9 @@
 
 #include <llvm-c/Analysis.h>
 #include <llvm-c/Transforms/Scalar.h>
+#if HAVE_LLVM >= 0x0700
+#include <llvm-c/Transforms/Utils.h>
+#endif
 #include <llvm-c/BitWriter.h>