x86: Fix tabs in access.c

Tabs and spaces in this file are inconsistent and don't follow the
coding style.  Correct them to adhere to the standard and make it easier
to work in this file.

No functional change intended.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Message-Id: <20211110212001.3745914-13-aaronlewis@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>