Make mariadb crc32 lib platform independent

It looks strange that someone can make use of 2 crc libraries
(Power64 or AArch64) at the same time.

The patch sets macros 'CRC32_LIBRARY' to make platform independence as an optional crc32 library.

Change-Id: I68bbf73cafb6a12f7fb105ad57d117b114a8c4af
Signed-off-by: Yuqi Gu <yuqi.gu@arm.com>