sched: Support adding timers to the start of timer_list

If sched_add_timer() is called on a timer that would make it the new
head of the list, then add it and signal the board code that the timer
should be rescheduled.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/generic/misc.h

@@ -11,6 +11,7 @@ void console_sendf(const struct command_encoder *ce, va_list args);
 uint32_t timer_from_us(uint32_t us);
 uint8_t timer_is_before(uint32_t time1, uint32_t time2);
 uint32_t timer_read_time(void);
+void timer_kick(void);
 void timer_periodic(void);
 
 void *dynmem_start(void);

src/generic/timer_irq.c

@@ -10,7 +10,7 @@
 #include "board/timer_irq.h" // timer_dispatch_many
 #include "basecmd.h" // stats_note_sleep
 #include "command.h" // shutdown
-#include "sched.h" // sched_timer_kick
+#include "sched.h" // sched_timer_dispatch
 
 DECL_CONSTANT(CLOCK_FREQ, CONFIG_CLOCK_FREQ);