Fix RocksDB SIGILL error on Raspberry PI 4 (#7233)

Fix RocksDB SIGILL error on Raspberry PI 4 (#7233)

Summary:
Issue：https://github.com/facebook/rocksdb/issues/7042

No PMULL runtime check will lead to SIGILL on a Raspberry pi 4.

Leverage 'getauxval' to get Hardware-Cap to detect whether target
platform does support PMULL or not in runtime.

Consider the condition that the target platform does support crc32 but not support PMULL.
In this condition, the code should leverage the crc32 instruction
rather than skip all hardware crc32 instruction.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7233

Reviewed By: jay-zhuang

Differential Revision: D23790116

fbshipit-source-id: a3ebd821fbd4a38dd2f59064adbb7c3013ee8140
(cherry picked from commit 29f7bbef995bdf83098963799c66af742e95373f)