Revert "build: llvm libs may not be in system search path, add rpath"

This reverts commit d9b983519c.

Unfortunately it seems like rpath is evaluated before LD_LIBRARY_PATH,
so this breaks e.g. steam, as well as any other user of that env var,
if the llvm path happens to be where other libs also reside.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76082
Reviewed-by: Tom Stellard <thomas.stellard@amd.com>
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>

configure.ac

@@ -1549,7 +1549,6 @@ if test "x$enable_gallium_llvm" = xyes; then
         LLVM_CXXFLAGS=`strip_unwanted_llvm_flags "$LLVM_CONFIG --cxxflags"`
         LLVM_INCLUDEDIR=`$LLVM_CONFIG --includedir`
         LLVM_LIBDIR=`$LLVM_CONFIG --libdir`
-        LLVM_LDFLAGS="-Wl,-rpath,$LLVM_LIBDIR $LLVM_LDFLAGS"
 
         AC_COMPUTE_INT([LLVM_VERSION_MAJOR], [LLVM_VERSION_MAJOR],
             [#include "${LLVM_INCLUDEDIR}/llvm/Config/llvm-config.h"])