Notice that the second argument to acpi_ec_query() is redundant,
because in the only case when it is not NULL, the value passed
through it is only checked against 0 and it can only be 0 when
acpi_ec_query() returns an error code, but its return value
is checked along with the value passed through its second
argument.

Accordingly, modify acpi_ec_query() to take only one argument
and while at it, change its handling of the case when
acpi_ec_transaction() returns an error so as to return that
error value to the caller right away.

No expected functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>