Revert "arm64: mm: Unmap kernel data/bss entirely from the linear map"

Revert "arm64: mm: Unmap kernel data/bss entirely from the linear map"

This reverts commit 63e0b6a5b6934d6a919d1c65ea185303200a1874.

Unmapping the kernel '.bss' appears to break KVM initialisation on some
devices, breaking the boot on popular platforms such as RaspberryPi3 and
4.

Revert this change for now so that we can revisit it in future.

Reported-by: Mark Brown <broonie@kernel.org>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/all/aicVyebkEMs6w6UV@sirena.co.uk
Link: https://lore.kernel.org/r/a1b27e97-182c-485d-a448-56c19c5de2c2@samsung.com
Signed-off-by: Will Deacon <will@kernel.org>