video: fbdev: pxa3xx_gcu: 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.

This also fixes the use of the "priv" variable in QERROR(), since it was
pointing to struct timer_list, not struct pxa3xx_gcu_priv.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Himanshu Jha <himanshujha199640@gmail.com>
[b.zolnierkie: trivial build fixup]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>