[PATCH 0/4] arm64: align KPTI interface with x86

ARM64 supports KPTI, but is missing some user interface features such as
a debugfs entry compared to the x86 implementation.

Add the nopti argument, update the documentation so that ARM64 as well
as x86 supports nopti and kpti, and add a debugfs entry to check the
status of the kpti on a running machine.

--Mark Langsdorf