Revert "ANDROID: arm64: Always WARN in ioremap"

This reverts commit c7cf3d5d.

Driver using memremap() will potentially behind the hood use ioremap.
But as this is normal memory, the MMIO guard registration would fail in
the hypervisor (which is expected and normal) and by extension trigger
this warning.

This behaviour is completely normal and there is no need to alarm anyone
with a warning here. So remove it until we come with a better solution.

Bug: 278749606
Bug: 243642516
Bug: 343680567
Change-Id: I8f51f264c32ab825779413d50b644885db953282
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>