ACPI / EC: Remove irqs_disabled() check.

The following commit merges polling and interrupt modes for EC driver:
  Commit: 2a84cb9852f52c0cd1c48bca41a8792d44ad06cc Mon Sep 17 00:00:00 2001
  Subject: ACPI: EC: Merge IRQ and POLL modes
The irqs_disabled() check introduced in it tries to fall into busy polling
mode when the context of ec_poll() cannot sleep.

Actually ec_poll() is ensured to be invoked in the contexts that can sleep
(from a sysfs /sys/kernel/debug/ec/ec0/io access, or from
acpi_evaluate_object(), or from acpi_ec_gpe_poller()). Without the MSI
quirk, we never saw the udelay() logic invoked. Thus this check is useless
and can be removed.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/ec.c

@@ -504,8 +504,7 @@ static int ec_poll(struct acpi_ec *ec)
 			msecs_to_jiffies(ec_delay);
 		unsigned long usecs = ACPI_EC_UDELAY_POLL;
 		do {
-			/* don't sleep with disabled interrupts */
-			if (EC_FLAGS_MSI || irqs_disabled()) {
+			if (EC_FLAGS_MSI) {
 				usecs = ACPI_EC_MSI_UDELAY;
 				udelay(usecs);
 				if (ec_transaction_completed(ec))