Revert "sgx: with v3.7.x: mm: kill vma flag VM_RESERVED and mm->reserved_vm counter"

This reverts commit 97171865bd68386f148c75d4ac473e4e2db9a1eb.

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
sgx: with v3.7.x: mm: kill vma flag VM_RESERVED and  mm->reserved_vm counter

redo of commit:
https://github.com/RobertCNelson/ti-sdk-pvr/commit/97171865bd68386f148c75d4ac473e4e2db9a1eb

didn't really care to debug why LINUX_VERSION_CODE wasn't working...

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>