arm64/mm: add explicit struct_mm argument to __create_mapping()

Currently, swapper_pg_dir and idmap_pg_dir share the init_mm mm_struct
instance. To allow the introduction of other pg_dir instances, for instance,
for UEFI's mapping of Runtime Services, make the struct_mm instance an
explicit argument that gets passed down to the pmd and pte instantiation
functions. Note that the consumers (pmd_populate/pgd_populate) of the
mm_struct argument don't actually inspect it, but let's fix it for
correctness' sake.

Change-Id: Iabd119a2c8ed0ae55839eb9c5376c5555597da6f
Acked-by: Steve Capper <steve.capper@linaro.org>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Git-commit: e1e1fddae74b72d0415965821ad00fe39aac6f13)
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[rvaswani@codeaurora.org: fixed merge conflicts]
Signed-off-by: Rohit Vaswani <rvaswani@codeaurora.org>