Make `camcontrol modepage` to use 10 byte commands.

Make `camcontrol modepage` to use 10 byte commands.

While old devices may not support 10 byte MODE SENSE/MODE SELECT commands,
new ones may not be able to report all mode pages with 6 byte commands.

This patch makes camcontrol by default start with 10 byte commands and
fall back to 6 byte on ILLEGAL REQUEST error, or 6 byte can be forced.

MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.