swr: use LLVM version string instead of re-computing it

Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

src/gallium/drivers/swr/swr_screen.cpp

@@ -69,8 +69,7 @@ static const char *
 swr_get_name(struct pipe_screen *screen)
 {
    static char buf[100];
-   snprintf(buf, sizeof(buf), "SWR (LLVM %u.%u, %u bits)",
-            HAVE_LLVM >> 8, HAVE_LLVM & 0xff,
+   snprintf(buf, sizeof(buf), "SWR (LLVM " MESA_LLVM_VERSION_STRING ", %u bits)",
             lp_native_vector_width);
    return buf;
 }