[arch][arm] add ARM SMP support

-Also adds support to the following ARM-related drivers:
    dev/cache/pl310
    dev/interrupt/arm_gic
    dev/timer/arm_cortex_a9

dev/timer/arm_cortex_a9/arm_cortex_a9_timer.c

@@ -189,6 +189,19 @@ void arm_cortex_a9_timer_init(addr_t _scu_control_base, uint32_t freq)
 {
     scu_control_base = _scu_control_base;
 
+    arm_cortex_a9_timer_init_percpu();
+
+    /* save the timer frequency for later calculations */
+    timer_freq = freq;
+
+    /* precompute the conversion factor for global time to real time */
+    fp_32_64_div_32_32(&timer_freq_msec_conversion, timer_freq, 1000);
+    fp_32_64_div_32_32(&timer_freq_usec_conversion_inverse, 1000000, timer_freq);
+    fp_32_64_div_32_32(&timer_freq_msec_conversion_inverse, 1000, timer_freq);
+}
+
+void arm_cortex_a9_timer_init_percpu(void)
+{
     /* disable timer */
     TIMREG(TIMER_CONTROL) = 0;
 
@@ -198,14 +211,7 @@ void arm_cortex_a9_timer_init(addr_t _scu_control_base, uint32_t freq)
     /* ack any irqs that may be pending */
     TIMREG(TIMER_ISR) = 1;
 
-    /* save the timer frequency for later calculations */
-    timer_freq = freq;
-
-    /* precompute the conversion factor for global time to real time */
-    fp_32_64_div_32_32(&timer_freq_msec_conversion, timer_freq, 1000);
-    fp_32_64_div_32_32(&timer_freq_usec_conversion_inverse, 1000000, timer_freq);
-    fp_32_64_div_32_32(&timer_freq_msec_conversion_inverse, 1000, timer_freq);
-
+    /* register the platform tick on each cpu */
     register_int_handler(CPU_PRIV_TIMER_INT, &platform_tick, NULL);
     unmask_interrupt(CPU_PRIV_TIMER_INT);
 }

dev/timer/arm_cortex_a9/include/dev/timer/arm_cortex_a9.h

@@ -25,3 +25,4 @@
 #include <sys/types.h>
 
 void arm_cortex_a9_timer_init(addr_t scu_control_base, uint32_t freq);
+void arm_cortex_a9_timer_init_percpu(void);