ACPI: EC: Abort address space access upon error

When a multi-byte address space access is requested, acpi_ec_read()/
acpi_ec_write() is being called multiple times.

Abort such operations if a single call to acpi_ec_read() /
acpi_ec_write() fails, as the data read from / written to the EC
might be incomplete.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>