Revert "block: prevent access to NULL pointer in req->part"
Revert "block: prevent access to NULL pointer in req->part"

This reverts commit f97d4f6148f74376f71f661682c71da30ecbaf13.
Although this check prevents NULL reference, it hides the real problem.
Requests that wish to avoid statistics update have to disable the
REQ_IO_STAT flag, otherwise req->part is expected to be initialized.

Change-Id: I680b95ab9aa668612d948770347929ffde30aeab
Signed-off-by: Dolev Raviv <3d75773ad3271f97975e35fbf4c96b1bb9f3e9d6@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas