llvm: move libLLVM.so.N.M to llvm-libllvm package

llvm: move libLLVM.so.N.M to llvm-libllvm package

Neither MAJOR_VER nor MINOR_VER are defined, so libLLVM.so.N.M ends up
in the main libllvm package rather than the llvm-libllvm package, as
expected. Fix this by properly using two-component version.

Fixes: db3bf550a372 ("llvm: Update to 18.1.0 RC4")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>