media: i2c: ov9282: Correct the exposure offset

The datasheet lists that "Maximum exposure time is frame
length -25 row periods, where frame length is set by
registers {0x380E, 0x380F}".
However this driver had OV9282_EXPOSURE_OFFSET set to 12
which allowed that restriction to be violated, and would
result in very under-exposed images.

Correct the offset.

Fixes: 14ea315 ("media: i2c: Add ov9282 camera sensor driver")
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>

Author: 6by9

drivers/media/i2c/ov9282.c

@@ -40,7 +40,7 @@
 /* Exposure control */
 #define OV9282_REG_EXPOSURE	0x3500
 #define OV9282_EXPOSURE_MIN	1
-#define OV9282_EXPOSURE_OFFSET	12
+#define OV9282_EXPOSURE_OFFSET	25
 #define OV9282_EXPOSURE_STEP	1
 #define OV9282_EXPOSURE_DEFAULT	0x0282