scsi: ufs: fix a possible kernel info leak to userspace

This change fixes a possible info leak from kernel into userspace, since
two buffers were allocated with kmalloc() and never set their memory
region to 0.
Now, they are being allocated with kzalloc that fixes this issue

Change-Id: I23012ae8d3611c561511775362c3014b9a8be522
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>