chips: apollo3: stimer: Reset timer on creation

When creating the STimer reset the count to zero. This way the timer
roughly aligns to the total time the system has been running, otherwise
the timer starts at a random value.

Signed-off-by: Alistair Francis <alistair@alistair23.me>

chips/apollo3/src/stimer.rs

@@ -102,11 +102,16 @@ pub struct STimer<'a> {
 
 impl<'a> STimer<'_> {
     // Unsafe bc of use of STIMER_BASE internally
-    pub const fn new() -> STimer<'a> {
-        STimer {
+    pub fn new() -> STimer<'a> {
+        let timer = STimer {
             registers: STIMER_BASE,
             client: OptionalCell::empty(),
-        }
+        };
+
+        // Reset so that time starts at 0
+        let _ = timer.reset();
+
+        timer
     }
 
     pub fn handle_interrupt(&self) {