Revert "arm64: Treat ESR_ELx as a 64-bit register"

This reverts commit 46ddfb9d which is
commit 8d56e5c5 upstream.

It broke the abi and the change that was needing it was reverted so this
is no longer needed as well.

Bug: 161946584
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I422962a7facff61a07f620c793282691e5d73717