sony_acpi: Add backlight support to the sony_acpi v2

Enable the sony_acpi driver to use the backlight subsysyem for adjusting
the monitor brightness.  Old way of changing the brightness will be still
available for compatibility with existing tools.

Signed-off-by: Alessandro Guido <alessandro.guido@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/sony_acpi.c

@@ -76,6 +76,14 @@ static struct sony_acpi_value {
 	int			valid;	 /* Has ever been set */
 	int			debug;	 /* active only in debug mode ? */
 } sony_acpi_values[] = {
+	{
+		.name		= "brightness",
+		.acpiget	= "GBRT",
+		.acpiset	= "SBRT",
+		.min		= 1,
+		.max		= SONY_MAX_BRIGHTNESS,
+		.debug		= 0,
+	},
 	{
 		.name		= "brightness_default",
 		.acpiget	= "GPBR",