Replaced get_tick_per_sec() by NANOSECONDS_PER_SECOND

This patch replaces get_ticks_per_sec() calls with the macro
NANOSECONDS_PER_SECOND. Also, as there are no callers, get_ticks_per_sec()
is then removed.  This replacement improves the readability and
understandability of code.

For example,

    timer_mod(fdctrl->result_timer,
	      qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + (get_ticks_per_sec() / 50));

NANOSECONDS_PER_SECOND makes it obvious that qemu_clock_get_ns
matches the unit of the expression on the right side of the plus.

Signed-off-by: Rutuja Shah <rutu.shah.26@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/hw/misc/macio/macio.c b/hw/misc/macio/macio.c
index 6e94e3b..be03926 100644
--- a/hw/misc/macio/macio.c
+++ b/hw/misc/macio/macio.c
@@ -254,7 +254,7 @@
     uint64_t systime = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
     uint64_t kltime;
 
-    kltime = muldiv64(systime, 4194300, get_ticks_per_sec() * 4);
+    kltime = muldiv64(systime, 4194300, NANOSECONDS_PER_SECOND * 4);
     kltime = muldiv64(kltime, 18432000, 1048575);
 
     switch (addr) {