actually the timer init use the interrupt_init as init callback
which make the interrupt and timer implementation difficult to follow
so now rename it as int timer_init(void) and use interrupt_init for interrupt
btw also remane the corresponding file to the functionnality implemented
as ixp arch implement two timer - one based on interrupt - so all the timer
related code is moved to timer.c
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
