[PATCH v3] linux-gen: timer: enhance timer expire scalability

[TianyuLi0]

Use stash and pre-allocated memory to store tick_buf index, so timer_expire can find expire tick_buf index with hash function without walk through all tick_buf.

Addtional overhead introduced to timer start and cancel operation. Expire operation cost remain constant.

Timer set and cancel operation cycles Base 69 Current 139

Expire operation cycles Timer num. 10 100 1000 Base 37 38 190 Current 40 39 37