sparc: Update cpu_init.c to use generic timer infrastructure

Introduce the CONFIG_SYS_TIMER_* macros in include/asm/config.h to make use
of the generic timer infrastructure in lib/time.c.

Created a timer_init() function to initialize the timer hardware and update
the #ifdef in board_init_f to allow this function to be called during the
start-up sequence.

Signed-off-by: Francois Retief <fgretief@spaceteq.co.za>

arch/sparc/lib/interrupts.c

@@ -81,11 +81,6 @@ void timer_interrupt(struct pt_regs *regs)
 	timestamp++;
 }
 
-ulong get_timer(ulong base)
-{
-	return (timestamp - base);
-}
-
 void timer_interrupt_init(void)
 {
 	int irq;