[CRYPTO] cts: Init SG tables

Steps to reproduce:

	modprobe tcrypt		# with CONFIG_DEBUG_SG=y

testing cts(cbc(aes)) encryption
test 1 (128 bit key):
------------[ cut here ]------------
kernel BUG at include/linux/scatterlist.h:65!
invalid opcode: 0000 [1] PREEMPT SMP DEBUG_PAGEALLOC
CPU 0 
Modules linked in: tea xts twofish twofish_common tcrypt(+) [maaaany]
Pid: 16151, comm: modprobe Not tainted 2.6.26-rc4-fat #7
RIP: 0010:[<ffffffffa0bf032e>]  [<ffffffffa0bf032e>] :cts:cts_cbc_encrypt+0x151/0x355
RSP: 0018:ffff81016f497a88  EFLAGS: 00010286
RAX: ffffe20009535d58 RBX: ffff81016f497af0 RCX: 0000000087654321
RDX: ffff8100010d4f28 RSI: ffff81016f497ee8 RDI: ffff81016f497ac0
RBP: ffff81016f497c38 R08: 0000000000000000 R09: 0000000000000011
R10: ffffffff00000008 R11: ffff8100010d4f28 R12: ffff81016f497ac0
R13: ffff81016f497b30 R14: 0000000000000010 R15: 0000000000000010
FS:  00007fac6fa276f0(0000) GS:ffffffff8060e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f12...