[ACPI] Enable Embedded Controller (EC) interrupt mode by default

"ec_intr=0" reverts to polling
"ec_burst=" no longer exists.

Signed-off-by: Len Brown <len.brown@intel.com>
Acked-by: Luming Yu <luming.yu@intel.com>

Documentation/kernel-parameters.txt

@@ -452,6 +452,11 @@ running once the system is up.
 
 	eata=		[HW,SCSI]
 
+	ec_intr=	[HW,ACPI] ACPI Embedded Controller interrupt mode
+			Format: <int>
+			0: polling mode
+			non-0: interrupt mode (default)
+
 	eda=		[HW,PS2]
 
 	edb=		[HW,PS2]