sparc64: Fix boot on T4 and later.

If we don't put the NG4fls.o object into the same part of
the link as the generic sparc64 objects for fls() and __fls()
then the relocation in the branch we use for patching will
not fit.

Move NG4fls.o into lib-y to fix this problem.

Fixes: 46ad8d2d

 ("sparc64: Use sparc optimized fls and __fls for T4 and above")
Signed-off-by: David S. Miller <davem@davemloft.net>
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Tested-by: Anatoly Pugachev <matorola@gmail.com>