Fix get_elf_hwcap always return 0 on HarmonyOS NEXT.

[peerless2012]

This is a fix for get_elf_hwcap on HarmonyOS NEXT device, see #5950 .

By default, get_elf_hwcap will use get_elf_hwcap_from_proc_self_auxv, and it need to read /proc/self/auxv to get the hwcap.

And on HarmonyOS NEXT, when build hap with debug type, /proc/self/auxv is readable. But when build hap with release, /proc/self/auxv can't read. That will make g_hwcaps and g_hwcaps2 to 0 when use release build type.

HarmonyOS NEXT has <sys/auxv.h>, so use getauxval() in <sys/auxv.h>, just like android do.

This issue will Influence the methods below:

auto asimdhp = ncnn::cpu_support_arm_asimdhp();
auto cpuid = ncnn::cpu_support_arm_cpuid();
auto asimddp = ncnn::cpu_support_arm_asimddp();
auto asimdfhm = ncnn::cpu_support_arm_asimdfhm();
auto bf16 = ncnn::cpu_support_arm_bf16();
auto i8mm = ncnn::cpu_support_arm_i8mm();
auto sve = ncnn::cpu_support_arm_sve();
auto sve2 = ncnn::cpu_support_arm_sve2();
auto svebf16 = ncnn::cpu_support_arm_svebf16();
...

Due my test, after the change, cpuid and sve2 art still 0, others works fine.

[tencent-adm]

All committers have signed the CLA.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.42%. Comparing base (8211930) to head (b49696c).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5951      +/-   ##
==========================================
+ Coverage   95.37%   95.42%   +0.05%     
==========================================
  Files         816      819       +3     
  Lines      267270   268184     +914     
==========================================
+ Hits       254907   255922    +1015     
+ Misses      12363    12262     -101     

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[nihui]

Thanks for your contribution !