iommu: msm: Correct address range in access_control feature

With access_control feature, we want to block
peripheral access to only kernel text region. By
aligning kernel_start and kernel_end address by
2MB we are blocking access to region outside
of kernel text region which is wrong. So fix this
and remove the alignment of addresses.

Change-Id: Idefb8f41a59a6de1fb581cbfb6b23fef375fffd4
Signed-off-by: Susheel Khiani <skhiani@codeaurora.org>