arm64/efi: remove idmap manipulations from UEFI code

Now that we have moved the call to SetVirtualAddressMap() to the stub,
UEFI has no use for the ID map, so we can drop the code that installs
ID mappings for UEFI memory regions.

Change-Id: I4adfbd1e664c6cc4420b5100cb32725d97cbf585
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Git-commit 9679be103108926cfe9e6fd2f6829cefa77e47b0
[rvaswani@codeaurora.org: fixed merge conflicts]
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


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