drivers: qcom: fix compilation errors

Fix compilation errors when compiling with 4.9 kernel on arm
architectures. do_div() likes its argument to be a uint64_t instead of a
signed value.

Change-Id: I81cf23fd649120a35a21f1aabc9d82192e330b67
Signed-off-by: Lina Iyer <ilina@codeaurora.org>