BACKPORT: FROMLIST: mm: ASLR: use get_random_long()

(cherry picked from commit https://lkml.org/lkml/2016/2/4/833

)

Replace calls to get_random_int() followed by a cast to (unsigned long)
with calls to get_random_long().  Also address shifting bug which, in case
of x86  removed entropy mask for mmap_rnd_bits values > 31 bits.

Bug: 26963541
Signed-off-by: Daniel Cashman <dcashman@android.com>
Signed-off-by: Daniel Cashman <dcashman@google.com>
Git-commit: 000d53cb73049f5539762e33d44437c8df99fe38
Git-repo: https://android.googlesource.com/kernel/common.git


[schikk@codeaurora.org conflict resolved]
CRs-Fixed: 1066871
Change-Id: I9c77b70f386531b0c609ea31f7290002e5484896
Signed-off-by: Swetha Chikkaboraiah <schikk@codeaurora.org>