ACPI: EC: Drop unneeded result variable from ec_write()

Return the acpi_ec_write() return value directly instead of storing it
in another redundant variable.
Reported-by: NZeal Robot <zealci@zte.com.cn>
Signed-off-by: Nye xingchen <ye.xingchen@zte.com.cn>
[ rjw: Subject and changelog edits ]
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/ec.c

@@ -917,14 +917,10 @@ EXPORT_SYMBOL(ec_read);
 
 int ec_write(u8 addr, u8 val)
 {
-	int err;
-
 	if (!first_ec)
 		return -ENODEV;
 
-	err = acpi_ec_write(first_ec, addr, val);
-
-	return err;
+	return acpi_ec_write(first_ec, addr, val);
 }
 EXPORT_SYMBOL(ec_write);