sparc64: Fix build error in flush_tsb_user_page

Patch "sparc64: Add 64K page size support"
unconditionally used __flush_huge_tsb_one_entry()
which is available only when hugetlb support is
enabled.

Another issue was incorrect TSB flushing for 64K
pages in flush_tsb_user().

Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>