nios2: Reload timer count in reset_timer()

nios2: Reload timer count in reset_timer()

   When the timestamp is incremented via interrupt and the interrupt
   period is greater than 1 msec, successive calls to get_timer() can
   produce inaccurate timing since the interrupts are asynchronous
   to the timing loop. For example, with an interrupt period of 10 msec
   two successive calls to get_timer() could indicate an elapsed time
   of 10 msec after only several hundred usecs -- depending on when
   the next interrupt actually occurs. This behavior can cause
   reliability issues with components such as CFI and NAND.

   This can be remedied by calling reset_timer() prior to establishing
   the base timestamp with get_timer(0), provided reset_timer()
   resets the hardware timer (rather than simply resetting only the
   timestamp). This has the effect of synchronizing the interrupts
   (and the advance of the timestamp) with the timing loop.

Signed-off-by: Scott McNutt <smcnutt@psyent.com>