arm64: make Timer Interrupt Frequency selectable
arm64: make Timer Interrupt Frequency selectable

It allows a selectable timer interrupt frequency of 100, 250, 300 and 1000 HZ.
We will get better performance when choose a suitable frequency in some scene.

Cc: Will Deacon <b913f13ef92ac157955c954ccaaff7be065faba4@arm.com>
Signed-off-by: Kefeng Wang <28dcd0de9b54e95b3f55a3f93046a1211e1d9a5a@huawei.com>
Signed-off-by: Catalin Marinas <15ce75b290ebaf27c3f9fd73ab848685ed3d8261@arm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs