V4L/DVB (4376): Make it possible for run-time calculation of control min/max in pvrusb2

The internal control implementation in the pvrusb2 driver normally
encodes integer range limits using literal values in a const
structure.  This change adds two function pointers, which if not null
will be called through in order to determine integer min / max
values.

Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h b/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h
index 14800b6..74c125a 100644
--- a/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h
+++ b/drivers/media/video/pvrusb2/pvrusb2-hdw-internal.h
@@ -80,6 +80,8 @@
 
 	/* Control's implementation */
 	pvr2_ctlf_get_value get_value;      /* Get its value */
+	pvr2_ctlf_get_value get_min_value;  /* Get minimum allowed value */
+	pvr2_ctlf_get_value get_max_value;  /* Get maximum allowed value */
 	pvr2_ctlf_set_value set_value;      /* Set its value */
 	pvr2_ctlf_val_to_sym val_to_sym;    /* Custom convert value->symbol */
 	pvr2_ctlf_sym_to_val sym_to_val;    /* Custom convert symbol->value */