staging/lustre/libcfs: cleanup linux-crypto

We don't need to implement crc32 and crc32pclmul on our own.
The crc32-pclmul support was merged into the 3.8 kernel in commit
78c37d1, no need to keep a local copy in Lustre anymore.
The crc32 implementation is identical to crypto-crc32. So drop
Lustre's private implementation and select kernel crypto in Kconfig.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>