staging: vc04_services: 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.

Additionally removes invalid NULL check, as pointed out by Dan Carpenter.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Michael Zoran <mzoran@crowfest.net>
Cc: Keerthi Reddy <keerthigd4990@gmail.com>
Cc: linux-rpi-kernel@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: devel@driverdev.osuosl.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>