ACPI / EC / PM: Fix names of functions that block/unblock EC transactions

The names of the functions used for blocking/unblocking EC
transactions during suspend/hibernation suggest that the transactions
are suspended and resumed by them, while in fact they are disabled
and enabled.  Rename the functions (and the flag used by them) to
better reflect what they really do.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>