arm64: mm: Do not create 1GB mappings if FORCE_PAGES is enabled

With CONFIG_FORCE_PAGES enabled, we break down the section mappings
into 4K page mappings. For 1GB mappings, remapping the pages into 4K
chunks becomes unnecessarily complicated. Skip creating the 1GB mapping
if we know it's going to be separated into 4K mappings.

Change-Id: I991768210ed6e1c1e19faf0d5d851d550e51a8c6
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>