Use timer_init() instead of board supplied interrupt_init()

The timer on AT91CAP9/AT91SAM9 is supplied by the SoC, and not by
the board, so use timer_init() instead of interrupt_init().

Signed-off-by: Stelian Pop <stelian@popies.net>
diff --git a/cpu/arm926ejs/at91cap9/timer.c b/cpu/arm926ejs/at91cap9/timer.c
index 4110e15..c6df5bd 100644
--- a/cpu/arm926ejs/at91cap9/timer.c
+++ b/cpu/arm926ejs/at91cap9/timer.c
@@ -41,7 +41,7 @@
 AT91PS_PITC p_pitc;
 
 /* nothing really to do with interrupts, just starts up a counter. */
-int interrupt_init(void)
+int timer_init(void)
 {
 	/*
 	 * Enable PITC Clock