timer_irq: Rename generic/timer.c to generic/timer_irq.c

Rename the file to make it clear that the code is helper functions for
boards with irq based timers.

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

src/generic/timer_irq.c

@@ -7,6 +7,7 @@
 #include "autoconf.h" // CONFIG_CLOCK_FREQ
 #include "board/irq.h" // irq_disable
 #include "board/misc.h" // timer_from_us
+#include "board/timer_irq.h" // timer_dispatch_many
 #include "command.h" // shutdown
 #include "sched.h" // sched_timer_kick
 

src/generic/timer_irq.h

@@ -0,0 +1,6 @@
+#ifndef __GENERIC_TIMER_IRQ_H
+#define __GENERIC_TIMER_IRQ_H
+
+void timer_dispatch_many(void);
+
+#endif // timer_irq.h