ec/google/chromeec/acpi: Add MKBP support

Allow EC to send an interrupt using ACPI SMI when a MKBP event
is available. This will be used by the sensor stack.

Update all ACPI branch except those without sensors with:
for i in $(find . -name ec.h -exec grep -l MAINBOARD_EC_SCI_EVENTS {} \+
| cut -d '/' -f 2 | grep -v -e cyan -e lars); do
  echo $i
  cd $i
  git diff ../lars/ec.h | patch -p 5
  cd -
done

BUG=b:27849483
BRANCH=none
TEST=Compile on Samus. Tested in Cyan branch.

Change-Id: I4766d1d56c3b075bb2990b6d6f59b28c91415776
Signed-off-by: Martin Roth <martinroth@google.com>
Original-Commit-Id: d3b9f76a26397ff619f630c5e3d043a7be1a5890
Original-Change-Id: I56c46ee17baee109b9b778982ab35542084cbd69
Original-Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/342364
Original-Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://review.coreboot.org/14854
Tested-by: build bot (Jenkins)
Reviewed-by: Duncan Laurie <dlaurie@google.com>

src/ec/google/chromeec/acpi/ec.asl

@@ -289,6 +289,13 @@ Device (EC0)
 		Notify (BAT0, 0x80)
 	}
 
+	// MKBP interrupt.
+	Method (_Q1A, 0, NotSerialized)
+	{
+		Store ("EC: MKBP", Debug)
+		Notify (CREC, 0x80)
+	}
+
 	/*
 	 * Dynamic Platform Thermal Framework support
 	 */

src/ec/google/chromeec/ec_commands.h

@@ -459,6 +459,9 @@ enum host_event_code {
 	/* Keyboard fastboot combo has been pressed */
 	EC_HOST_EVENT_KEYBOARD_FASTBOOT = 25,
 
+	/* Emulate MKBP event */
+	EC_HOST_EVENT_MKBP = 26,
+
 	/*
 	 * The high bit of the event mask is not used as a host event code.  If
 	 * it reads back as set, then the entire event mask should be