msm: pm-8x60: Update the identity mapping for LPAE

The pm code uses a known stable page table with an identity mapping
for coming in and out of power collapse. This table currently assumes
a standard two level page table. This is incompatible with the new
format for LPAE. Update the code to handle both the LPAE and non-LPAE
page tables for power collapse.

Change-Id: I58097744134207fac49d7ab2147ba34f2f244a94
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>