msm: Kconfig: Select ENABLE_HOLES_IN_ZONE for 7x30

Current configurations end up with holes in the middle of
the highmem zone. The vm system makes certain assumptions
about the lack of holes within a zone. Failure to account
for these holes can lead to crashes due to accessing
uninitialized page structures. Select ENABLE_HOLES_IN_ZONE
to ensure these holes are properly accounted for.

CRs-Fixed: 370223
Change-Id: Ie6588fb8430cf3f04b6e7efdf0c4314b526dc873
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>