ext4: load the crc32c driver if necessary

Obtain a reference to the cryptoapi and crc32c if we mount a
filesystem with metadata checksumming enabled.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --cc fs/ext4/Kconfig
Simple merge

diff --cc fs/ext4/ext4.h
Simple merge

diff --cc fs/ext4/super.c
Simple merge