sparc/led: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. Adds a static variable to hold timeout
value.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geliang Tang <geliangtang@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: sparclinux@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>