Adjust pac73xx sof detection, we were throwing away 2 bytes after the sof,
but one of those 2 actually is the first magic marker for the first MCU, as
we may need those markers in the future pass the 2 bytes to userspace, this
also simplifies the code :)

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>

p.s.

Matching userspace code has now been committed to my tree:
http://linuxtv.org/hg/~hgoede/v4l-dvb
diff -r 55d686bc5075 linux/drivers/media/video/gspca/pac7311.c
--- a/linux/drivers/media/video/gspca/pac7311.c	Fri Aug 22 22:51:29 2008 +0200
+++ b/linux/drivers/media/video/gspca/pac7311.c	Fri Aug 22 22:54:13 2008 +0200
@@ -70,7 +70,6 @@
 #define SENSOR_PAC7311 1
 
 	u8 sof_read;
-	u8 header_read;
 	u8 autogain_ignore_frames;
 
 	atomic_t avg_lum;
@@ -759,8 +758,6 @@
 /* Include pac common sof detection functions */
 #include "pac_common.h"
 
-#define HEADER_LENGTH 2
-
 /* this function is run at interrupt level */
 static void sd_pkt_scan(struct gspca_dev *gspca_dev,
 			struct gspca_frame *frame,	/* target */
@@ -834,22 +831,7 @@
 		gspca_frame_add(gspca_dev, INTER_PACKET, frame, tmpbuf, 4);
 		gspca_frame_add(gspca_dev, INTER_PACKET, frame,
 			pac7311_jpeg_header2, sizeof(pac7311_jpeg_header2));
-
-		sd->header_read = 0;
 	}
-
-	if (sd->header_read < HEADER_LENGTH) {
-		/* skip the variable part of the sof header */
-		int needed = HEADER_LENGTH - sd->header_read;
-		if (len <= needed) {
-			sd->header_read += len;
-			return;
-		}
-		data += needed;
-		len -= needed;
-		sd->header_read = HEADER_LENGTH;
-	}
-
 	gspca_frame_add(gspca_dev, INTER_PACKET, frame, data, len);
 }