sparc64: Convert timers to user timer_setup()

Switch to using the new timer_setup() and from_timer()
in LDOM Virtual I/O handshake.

Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>