drivers: timer: fix the bug for SMP

* fix the smp timer dirver bugs found in debug and test.
for smp case, GFRC is used as clock source, and local
internal timer is used to trigger time event.

* because 64-bits gfrc is used, so idle can be igored as no kernel
tick will be missed

Signed-off-by: Wayne Ren <wei.ren@synopsys.com>