fix valgrind reported errors

[thehajime]

PR #9 started to report various errors in circle ci test. what we can do next is:

• to suppress by an auxiliary file to tell valgrind ignored
• to fix those issue in lkl
• to fix issues and upstream them (which should be great!)

e.g.,
https://circleci.com/gh/lkl/linux/38#tests

 Syscall param preadv(vector) points to uninitialised byte(s)

  0x534E6D2: preadv (preadv.c:47)
  0x403BE4: fd_do_rw (posix-host.c:185)
  0x40351F: virtio_process_avail_one (virtio.c:127)
  0x40351F: virtio_process_avail (virtio.c:137)
  0x40351F: virtio_write (virtio.c:281)
  0x672FDE: __raw_writel (io.h:80)
  0x672FDE: writel (io.h:163)
  0x672FDE: vm_notify (virtio_mmio.c:287)
  0x671C94: virtqueue_notify (virtio_ring.c:396)
  0x6813BA: virtio_queue_rq (virtio_blk.c:230)
  0x643005: __blk_mq_run_hw_queue (blk-mq.c:794)
  0x642C54: blk_mq_run_hw_queue (blk-mq.c:884)
  0x6435AE: blk_sq_make_request (blk-mq.c:1398)
  0x638E6F: generic_make_request (blk-core.c:1969)
  0x638F37: submit_bio (blk-core.c:2021)
  0x48E577: submit_bh_wbc.isra.38 (buffer.c:3065)

anybody volunteer to tackle those is really appreciated !

[thehajime]

i've added a suppression file for valgrind PR #28 to ignore some errors.