V4L/DVB (12138): em28xx: add support for Silvercrest Webcam

This webcam uses a em2710 chipset, that identifies itself as em2820,
plus a mt9v011 sensor, and a DY-301P lens.

It needs a few different initializations than a normal em28xx device.

Thanks to Hans de Goede <hdegoede@redhat.com> and Douglas Landgraf
<dougsland@redhat.com> for providing the acces for the webcam during
this weekend, I could make a patch for it while returning back from
FISL/Fudcom LATAM 2009.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index 813ce45..d90fef4 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -107,6 +107,7 @@
 #define EM2860_BOARD_TERRATEC_AV350		  68
 #define EM2882_BOARD_KWORLD_ATSC_315U		  69
 #define EM2882_BOARD_EVGA_INDTUBE		  70
+#define EM2820_BOARD_SILVERCREST_WEBCAM           71
 
 /* Limits minimum and default number of buffers */
 #define EM28XX_MIN_BUF 4
@@ -360,6 +361,7 @@
 	EM28XX_NODECODER,
 	EM28XX_TVP5150,
 	EM28XX_SAA711X,
+	EM28XX_MT9V011,
 };
 
 enum em28xx_adecoder {
@@ -388,6 +390,7 @@
 	unsigned int max_range_640_480:1;
 	unsigned int has_dvb:1;
 	unsigned int has_snapshot_button:1;
+	unsigned int is_27xx:1;
 	unsigned int valid:1;
 
 	unsigned char xclk, i2c_speed;