[media] cx88: implemented sharpness control

This patch implements support for a sharpness control, using the luma
peaking filter feature of cx2388x.

[mchehab@redhat.com: use cx_andor instead of cx_write]
Signed-off-by: Istvan Varga <istvan_v@mailbox.hu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx88/cx88-core.c b/drivers/media/video/cx88/cx88-core.c
index 2e145f0a..20ad809 100644
--- a/drivers/media/video/cx88/cx88-core.c
+++ b/drivers/media/video/cx88/cx88-core.c
@@ -759,8 +759,8 @@
 	if (nocomb)
 		value |= (3 << 5); // disable comb filter
 
-	cx_write(MO_FILTER_EVEN,  value);
-	cx_write(MO_FILTER_ODD,   value);
+	cx_andor(MO_FILTER_EVEN,  0x7ffc7f, value); /* preserve PEAKEN, PSEL */
+	cx_andor(MO_FILTER_ODD,   0x7ffc7f, value);
 	dprintk(1,"set_scale: filter  0x%04x\n", value);
 
 	return 0;