UBI: Fastmap: Fix PEB array type

The PEB array is an array of __be32, so let's fix the
scan_pool() prototype accordingly.

CRs-Fixed: 975289
Change-Id: I3e596e6a8f7537bcfc58330ba899012e18998a54
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Richard Weinberger <richard@nod.at>
Git-commit: 2a130f1aa54c2fb35abfc4d66e0239c80d054210
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Nikhilesh Reddy <reddyn@codeaurora.org>