acpi: accept byte and word access to core ACPI registers

acpi: accept byte and word access to core ACPI registers

All ISA registers should be accessible as bytes, words or dwords
(if wide enough).  Fix the access constraints for acpi-pm-evt,
acpi-pm-tmr & acpi-cnt registers.

Fixes: 5d971f9e67 (memory: Revert "memory: accept mismatching sizes in memory_region_access_valid")
Fixes: afafe4bbe0 (apci: switch cnt to memory api)
Fixes: 77d58b1e47 (apci: switch timer to memory api)
Fixes: b5a7c024d2 (apci: switch evt to memory api)
Buglink: https://lore.kernel.org/xen-devel/20200630170913.123646-1-anthony.perard@citrix.com/T/
Buglink: https://bugs.debian.org/964793
BugLink: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=964247
BugLink: https://bugs.launchpad.net/bugs/1886318
Reported-By: Simon John <git@the-jedi.co.uk>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Message-Id: <20200720160627.15491-1-mjt@msgid.tls.msk.ru>
Cc: qemu-stable@nongnu.org
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>