ANDROID: ABI: Export vendor_hook to be used by memcgv2 optimization mechanism

Update whitelist for the vendor hook symbols used by unisoc in
abi_gki_aarch64_unisoc. Also changes happened to the abi_gki_aarch64.xml file.

3 function symbol(s) added
  'int __traceiter_android_rvh_memcgv2_calc_decayed_watermark(void *, struct mem_cgroup *)'
  'int __traceiter_android_rvh_memcgv2_init(void *, struct mem_cgroup *)'
  'int __traceiter_android_rvh_update_watermark(void *, u64, struct page_counter *)'

3 variable symbol(s) added
  'struct tracepoint __tracepoint_android_rvh_memcgv2_calc_decayed_watermark'
  'struct tracepoint __tracepoint_android_rvh_memcgv2_init'
  'struct tracepoint __tracepoint_android_rvh_update_watermark'

Bug: 258126391
Change-Id: Ia15fe6d89a4b0972bff0ec6eeb289e2ed93b9a30
Signed-off-by: zhaoyang.huang <zhaoyang.huang@unisoc.com>