Changeset cb8379d in rtems

leon: restart and load timer counter at initialization

Without this smp05 and smpthreadlife01 tests may fail
depending on how the boot loader initialized the GPTIMER.
Before the time counter stopped counting when reaching
zero, but tests could work since it could take 2^{32 us
before stopping.}

The timer driver will potentially overwrite this, but it
happens later due to the initialization order having
RTEMS_SYSINIT_CPU_COUNTER very early.

Update #4312.